JP2005005689A - Piezoelectric element and method for manufacturing the same - Google Patents

Abstract

The present invention provides a piezoelectric element having good piezoelectric characteristics and increasing the film formation rate to improve mass productivity and a method for manufacturing the same.
A piezoelectric element comprising a first electrode film, a second electrode film, and a piezoelectric thin film sandwiched between the first electrode film and the second electrode film, the piezoelectric thin film Is characterized by being an oxide piezoelectric thin film having an oxygen deficiency of greater than 0% and less than 10% with respect to the stoichiometric composition. A piezoelectric element provided with such a piezoelectric thin film having an oxygen deficiency has a large piezoelectricity compared to an oxide piezoelectric thin film in an oxidized state of stoichiometric composition, and such Since the film formation rate can be increased by manufacturing under conditions, mass productivity can be improved.
[Selection] Figure 5

Description

  The present invention relates to a piezoelectric element including a piezoelectric thin film and a manufacturing method thereof.

  In recent years, piezoelectric thin films have been processed into various piezoelectric elements depending on the purpose. In particular, they are widely used as functional electronic parts such as actuators that generate deformation by applying voltage, and sensors that generate voltage from element deformation. It's being used.

  For example, a method of performing fine control of a magnetic head position on a magnetic disk using a piezoelectric element has been studied (for example, Patent Document 1). This is because the recording density of the magnetic disk has increased, and the area of the 1-bit recording area has become smaller, and it has become difficult to obtain sufficient accuracy only by positioning the magnetic head with a conventional voice coil motor. Because it is. For this reason, in addition to positioning by a voice coil motor, a two-stage actuator configuration that performs high-precision positioning in a minute region using a piezoelectric element has been studied. The piezoelectric element unit used for this is composed of a pair of piezoelectric elements, and is arranged so that when one is expanded, the other contracts, so the magnetic head attached to the tip of the piezoelectric element unit is placed on the disk surface. Can be moved minutely with high accuracy.

  Such a piezoelectric element is generally manufactured by the following method. For example, a magnesium oxide single crystal substrate (MgO substrate) is used as the substrate. A (100) -oriented platinum film (Pt film) is formed on the MgO substrate. Then, a (001) -oriented lead zirconate titanate (PZT) thin film is formed on the Pt film. Further, after forming an electrode thin film on the PZT thin film, these thin films are processed into a predetermined shape by photolithography and etching processes. Thereafter, the MgO substrate is removed by an etching process or the like to produce a piezoelectric element.

  A sputtering method is generally used for producing the PZT thin film, and the film forming temperature is 550 ° C. to 650 ° C. When sputtering is performed at such a high temperature, lead (Pb) is re-evaporated from the PZT thin film during the sputtering film formation, so that the finally produced PZT thin film deviates from the stoichiometric composition due to the decrease in the Pb composition. Become. For this reason, in order to obtain a PZT thin film having a stoichiometric composition, for example, a composition containing about 20% excess of Pb as a sputtering target is formed, and by using this target, a Pb component in the PZT thin film is formed. It has been shown to prevent the decrease (for example, Non-Patent Document 1).

  However, in order to obtain a PZT thin film having a stoichiometric composition using a target containing Pb in excess, it is necessary to add oxygen gas to an inert gas as a discharge gas and perform sputter deposition under relatively high pressure conditions. is there. However, the film formation rate cannot be increased under such conditions. When used as a piezoelectric element, a PZT thin film requires a thickness of about 1 μm to 10 μm, and therefore, mass productivity is greatly reduced at a low film formation rate.

  In addition, in forming a PZT thin film for use in a semiconductor memory, it has been shown that sputtering is performed with a discharge gas pressure in a vacuum apparatus being relatively low in order to increase the deposition rate (for example, Patent Document 2). . When the discharge gas pressure is lowered, the Pb component in the produced film is likely to decrease. Therefore, in this method, a target having an excessive Pb composition corresponding to the discharge gas pressure is used to produce a PZT thin film having a stoichiometric composition. ing.

On the other hand, when the thin film produced to improve the piezoelectric properties of the PZT thin film contains Pb in excess of the stoichiometric composition and the crystal structure is rhombohedral, the piezoelectric constant d ₃₁ can be increased. It is disclosed (for example, Patent Document 3).
JP 2002-279742 A JP-A-6-49638 Japanese Patent No. 3341357 J. et al. Appl. Phys. 65 (4), 1666 (1989)

However, both the first and second examples of the piezoelectric element fabrication method described above aim to fabricate a PZT thin film having a stoichiometric composition, and thus have a relatively high oxygen partial pressure. It is necessary to perform sputter deposition in a discharge gas. The piezoelectric constant d ₃₁ of the PZT thin film formed at such a high oxygen partial pressure is generally small, and the film formation rate during sputtering cannot be increased. Therefore, large piezoelectric characteristics cannot be obtained, and mass productivity also decreases.

  On the other hand, in the third example of the method for manufacturing the piezoelectric element, the amount of Pb in the PZT thin film is set to be larger than the amount of titanium (Ti) and dizirconium (Zr) added. The ratio of the amount of oxygen (O) and Pb in the thin film is increased at the same rate, and oxygen vacancies are not generated. For this reason, it is necessary to add a large amount of oxygen at the time of film formation and to perform sputtering under conditions of a high discharge gas pressure, and the film formation rate cannot be increased. As a result, mass productivity decreases.

The present invention is based on the knowledge that the piezoelectric constant d ₃₁ can be improved and a piezoelectric element with good piezoelectric characteristics can be realized if the oxygen deficiency is within a certain range with respect to the oxide piezoelectric thin film. An object of the present invention is to provide a piezoelectric element that is favorable and has a high film forming rate to improve mass productivity and a method for manufacturing the same.

  In order to solve this problem, a piezoelectric element of the present invention includes a first electrode film, a second electrode film, a piezoelectric thin film sandwiched between the first electrode film and the second electrode film, The piezoelectric thin film is an oxide piezoelectric thin film having an oxygen deficiency of greater than 0% and 10% or less with respect to the stoichiometric composition.

  The present inventor has found that a piezoelectric element including a piezoelectric thin film having such an oxygen deficiency has higher piezoelectricity than an oxide piezoelectric thin film in an oxidized state having a stoichiometric composition. I found. Further, by manufacturing under such conditions, the deposition rate can be increased and the mass productivity can be improved. The oxygen deficiency is expressed as a percentage of the amount of oxygen in the produced oxide piezoelectric thin film, where the stoichiometric oxygen amount is 100.

In the piezoelectric element of the present invention, the piezoelectric thin film is a lead zirconate titanate represented by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1). When the oxygen deficiency ratio in the piezoelectric thin film is represented by (Y−Z) / (Y + 3), 0 <(Y−Z) / (Y + 3) ≦ 0.1. .

  The oxygen deficiency ratio (Y−Z) / (Y + 3) is an index indicating the ratio of oxygen deficiency when compared with a stoichiometrically oxidized state in which Pb is divalent and Zr and Ti are tetravalent. is there. Compared with the stoichiometric oxidation state, that is, Y = Z, oxygen vacancies show larger piezoelectric characteristics. However, when the oxygen deficiency ratio exceeds 10% (0.1), the piezoelectric characteristics decrease, so that 0 <(Y−Z) / (Y + 3) ≦ 0.1. If Y and Z are set, a PZT thin film having large piezoelectric characteristics can be obtained.

  In addition, the piezoelectric element of the present invention is characterized in that the degree of crystal orientation of the piezoelectric thin film in the direction parallel to the polarization axis is 70% or more. Thereby, a piezoelectric element having large piezoelectric characteristics can be realized.

  Note that the peak intensity ratio of X-ray diffraction is used for the degree of crystal orientation. In the case of a material whose polarization is in the (001) direction, it is obtained by (001) / Σ (hkl), and in the case where the polarization is in a (111) direction, it is obtained by (111) / Σ (hkl). Here, Σ (hkl) is derived from PZT when the upper and lower limits of 2θ are set in the minimum range in which (111) reflection can be measured from (001) reflection in θ-2θ measurement using a CuKα radiation source. It is the sum of the intensity of the reflection peaks.

  In addition, the piezoelectric element of the present invention is characterized in that the crystal structure of the piezoelectric thin film is a perovskite type tetragonal system and is crystal-oriented in the (001) direction. Thereby, when a tetragonal PZT thin film is used as the piezoelectric material, a large piezoelectric characteristic can be imparted to the piezoelectric element.

  In addition, the piezoelectric element of the present invention is characterized in that the crystal structure of the piezoelectric thin film is a perovskite rhombohedral system and is oriented in the (111) direction. Thereby, when a rhombohedral PZT thin film is used as the piezoelectric material, a large piezoelectric characteristic can be imparted to the piezoelectric element.

In addition, the piezoelectric element of the present invention may include a part of Pb in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1) , Manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), samarium (Sm), europium (Eu) and at least one element selected from ytterbium (Yb) It is characterized by that. In the composite oxide piezoelectric thin film to which one or more kinds of such elements are added, the piezoelectric characteristics can be further improved by making the amount of oxygen deficiency larger than 0% and smaller than 10%.

The piezoelectric element of the present invention is at least one selected from Ti and Zr in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1). A part of the element was selected from hafnium (Hf), iridium (Ir), silicon (Si), germanium (Ge), tin (Sn), cerium (Ce), praseodymium (Pr) and terbium (Tb) It is characterized by comprising a structure replaced with at least one kind of element. In a composite oxide piezoelectric thin film in which a part of at least one element selected from Ti and Zr is substituted with such an element, if the oxygen deficiency is larger than 0% and smaller than 10%, the piezoelectric characteristics are further improved. Can be improved.

In addition, the piezoelectric element of the present invention has at least one selected from Pb, Ti and Zr in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1). A part of one kind of element is a monovalent one-genus typical element, scandium (Sc), yttrium (Y), chromium (Cr), boron (B), aluminum (Al), gallium (Ga), indium (In ), Antimony (Sb), bismuth (Bi), lanthanum (La), neodymium (Nd), promethium (Pm), gadolinium (Gd), dysprodium (Dy), holmium (Ho), erbium (Er), thulium ( Tm) and lutetium (Lu) are replaced with at least one element selected from the elements. In a composite oxide piezoelectric thin film in which a part of at least one element selected from Pb, Ti and Zr is substituted with such an element, if the amount of oxygen deficiency is larger than 0% and smaller than 10%, the piezoelectricity is further increased. The characteristics can be improved.

  The piezoelectric element according to the present invention is characterized in that the piezoelectric thin film is a thin film produced by a sputtering method or a laser ablation method. This enables crystal growth of the oxide piezoelectric thin film while precisely controlling the amount of oxygen vacancies in a gas atmosphere controlled with high accuracy, and makes the distribution of oxygen vacancies in the film uniform. Can do. For example, even when a piezoelectric material is formed by a powder sintering method, oxygen deficiency occurs if fired in a low oxygen atmosphere. In this case, however, oxygen deficiency is likely to be localized, which reduces reliability. End up. In the case of chemical vapor deposition (CVD), unlike the sputtering method or laser ablation method, a film is formed by oxidation and decomposition of the reaction gas, so that the piezoelectric material has good piezoelectric characteristics at a low oxygen partial pressure. It is relatively difficult to form a body thin film.

Furthermore, the method for manufacturing a piezoelectric element of the present invention includes a step of forming a first electrode film on a substrate and a general formula A _{1 + Y} BO _{3 + Z} (where A and B are formed on the first electrode film). In the vacuum apparatus during film formation when an oxide piezoelectric thin film having a crystal orientation degree parallel to the polarization axis of 70% or more is formed by sputtering or laser ablation. A step of forming the oxygen partial pressure in a range of 1% or more and less than 10% of the total pressure, a step of forming a second electrode film on the oxide piezoelectric thin film, and a first electrode And a step of processing the film, the oxide piezoelectric thin film, and the second electrode film into a preset pattern shape.

  Thereby, the produced oxide piezoelectric thin film has a predetermined amount of oxygen deficiency uniformly present in the film, and a thin film having large piezoelectric characteristics can be obtained. When sputtering is performed with the oxygen partial pressure exceeding 10%, oxygen vacancies do not occur and the film formation rate cannot be increased. On the other hand, when the oxygen partial pressure is 1% or less, the ratio of crystals parallel to the polarization axis is lowered, and the piezoelectric characteristics are not improved. That is, in order to obtain the necessary piezoelectric characteristics, the degree of crystal orientation needs to be 70% or more. For this purpose, the oxygen partial pressure is required to be 1% or more. Further, since sputtering is performed at such a relatively low oxygen partial pressure, the film formation rate can be increased and the mass productivity can be improved.

  The degree of crystal orientation is determined as follows using the peak intensity ratio of X-ray diffraction. In the case of a material whose polarization is in the (001) direction, it is obtained by (001) / Σ (hkl), and in the case where the polarization is in a (111) direction, it is obtained by (111) / Σ (hkl). Here, Σ (hkl) is the reflection caused by PZT when the upper limit and the lower limit of 2θ are set within the minimum range in which (111) reflection can be measured from (001) reflection in θ-2θ measurement using a CuKα radiation source. It is the sum of peak intensities.

Furthermore, in the method for manufacturing a piezoelectric element according to the present invention, the oxide piezoelectric thin film has the general formula A _{1 + Y} BO _{3 + Z} (where A and B represent elements), and A is lead (Pb). And B is lead zirconate titanate composed of zirconium (Zr) and titanium (Ti), the crystal structure of which is a perovskite tetragonal system, and the crystal orientation is the (001) direction. Thereby, when tetragonal PZT is used as the piezoelectric material, a large piezoelectric characteristic can be imparted to the piezoelectric element.

Furthermore, in the method for manufacturing a piezoelectric element according to the present invention, the oxide piezoelectric thin film has the general formula A _{1 + Y} BO _{3 + Z} (where A and B represent elements), and A is lead (Pb). B is lead zirconate titanate composed of zirconium (Zr) and titanium (Ti), the crystal structure is a perovskite rhombohedral system, and the crystal orientation is in the (111) direction . Thereby, when rhombohedral PZT is used as the piezoelectric material, large piezoelectric characteristics can be imparted to the piezoelectric element.

In the above, the oxide piezoelectric thin film represented by A _{1 + Y} BO _{3 + Z} is based on the perovskite structure represented by ABO ₃ , and Y and Z are within the range of the perovskite structure. It shall be variable.

Furthermore, in the method for manufacturing a piezoelectric element of the present invention, a general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 is} used as a film forming source in the step of forming an oxide piezoelectric thin film by sputtering or laser ablation. When represented by _{+ Z} (where 0 <X <1), a target having a composition of 0 <Y <1 and −3 ≦ Z ≦ Y is used. As a result, a PZT thin film having large piezoelectric characteristics can be stably manufactured even when high-speed sputtering is performed at a relatively low pressure.

  Furthermore, the piezoelectric element manufacturing method of the present invention is a method for forming an oxide piezoelectric thin film by a sputtering method or a laser ablation method, wherein a gas introduction flow rate into the vacuum apparatus is a ratio of oxygen gas introduction flow rate to total gas introduction flow rate. Is 0.01 or more and less than 0.1. Accordingly, when performing high-speed sputtering at a relatively low pressure, an oxide piezoelectric thin film having a predetermined oxygen deficiency amount ratio can be obtained, high-speed film formation is possible, and productivity can be improved.

  By using an oxide piezoelectric thin film having oxygen vacancies in this way, a piezoelectric element having larger piezoelectric characteristics than before can be obtained, and film formation can be performed at a high speed, which improves the characteristics of the piezoelectric element. Improve mass productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the figure demonstrated below, the same code | symbol is attached | subjected about the same element and description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a perspective view of the piezoelectric element according to the first embodiment of the present invention. FIG. 1 also shows a drive power supply 5 for driving the piezoelectric element 10.

  The piezoelectric element 10 includes a first electrode film 1, an oxide piezoelectric thin film 2 formed on the first electrode film 1, and a second electrode formed on the oxide piezoelectric thin film 2. It is composed of a film 3. The first electrode film 1, the oxide piezoelectric thin film 2 and the second electrode film 3 are each formed by a thin film forming technique such as sputtering, and processed into a substantially rectangular parallelepiped shape shown in FIG. 1 by photolithography and etching processes. Is done.

  The dimensions of the piezoelectric element 10 are, for example, about 2 mm in the direction in which the expansion and contraction of the piezoelectric body, that is, the length direction (direction indicated by B in FIG. 1), the width direction is about 0.5 mm, and the thickness is about 3 μm. It is. In order to use the piezoelectric element 10 as an element, it is necessary to cause the initial polarization in the oxide piezoelectric thin film 2, but in this embodiment, the polarization direction is the direction indicated by the arrow A as shown in FIG. It is. This polarization vector does not necessarily have to be perpendicular to the film surface, and if it is oblique, its vertical component may be considered. That is, it is not necessary that all the domains of the oxide piezoelectric thin film 2 are polarized in the film thickness direction.

  In addition, when spontaneous polarization occurs naturally immediately after the film formation, the spontaneous polarization may be used as it is. Further, the shape of the piezoelectric element 10 is not necessarily a rectangular parallelepiped. For example, various shapes such as a trapezoidal shape and a triangular shape may be used according to the shape of the device to be used.

  The driving power source 5 is a power source that applies a predetermined voltage to the piezoelectric element 10, and a voltage is applied to the first electrode film 1 and the second electrode film 3, and the oxide piezoelectric thin film 2 is caused by this voltage. Extends and contracts.

With the above configuration, the piezoelectric element 10 can expand and contract in the direction indicated by the arrow B according to the voltage of the drive power supply 5. In the present embodiment, this expansion / contraction operation is used as an actuator. That is, it is possible to perform precise positioning of the controlled object by fixing one controlled end and fixing the controlled object to be controlled to the free end with the other end fixed substantially. it can. The amount of displacement per voltage depends on the piezoelectric constant d ₃₁ , which is one of the indices of piezoelectricity.

  In the present invention, the amount of oxygen vacancies in the oxide piezoelectric thin film 2 is greater than 0% and not more than 10%, desirably not less than 2%, not more than 7%, more desirably not less than 2%, and It is characterized by controlling to 5% or less. The present inventor has found that a piezoelectric element including such an oxide piezoelectric thin film having an oxygen deficiency has a large piezoelectric characteristic compared to an oxide piezoelectric thin film in an oxidized state having a stoichiometric composition. Found to have. Further, by manufacturing under such conditions, the deposition rate can be increased and the mass productivity can be improved.

By making the oxygen deficiency larger than 0% and 10% or less, the piezoelectric constant d ₃₁ can be increased, and as a result, the displacement of the piezoelectric element can be increased. For example, when a PZT thin film having a general formula of Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} is used, the oxygen deficiency ratio (YZ) / (Y + 3) is greater than 0, and 0.1 (that is, 10%) or less.

  If the oxygen deficiency is 2% or more and 7% or less, the variation in crystal orientation can be suppressed, and the variation in displacement can be made relatively small even if the variation in oxygen deficiency occurs. This is desirable because the manufacturing yield can be improved. Furthermore, if the oxygen deficiency amount is 2% or more and 5% or less, the variation of the displacement amount with respect to the oxygen deficiency amount can be further reduced. Therefore, it is more desirable because the manufacturing yield can be further improved.

  Furthermore, it is desirable to make the crystal orientation so that the polarization axis is in the film thickness direction. For example, it is desirable to orient in the (001) direction for a tetragonal PZT thin film and in the (111) direction for a rhombohedral PZT thin film.

Hereinafter, a specific manufacturing method will be described by taking as an example a case where a PZT thin film represented by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} is formed by sputtering as the oxide piezoelectric thin film 2. The results of measuring the piezoelectric characteristics will be described.

  FIG. 2 shows a cross-sectional view of the main steps of the method for manufacturing the piezoelectric element 10 of the present embodiment.

  A (100) -oriented MgO substrate is used as the substrate. On this MgO substrate 15, the Pt film 1, which is a 100-nm-thick (100) -oriented first electrode film, has a substrate temperature of 500 ° C. and an argon (Ar) gas at a discharge gas pressure of 0.5 Pa. It was formed by sputtering.

Next, a PZT thin film 2 which is an oxide piezoelectric thin film having a thickness of 5 μm was formed on the Pt film 1. FIG. 2A is a cross-sectional view showing a state in which the PZT thin film 2 is formed. As a target composition at this time, when represented by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1), X = 0.58 and Y = 0 A target consisting of .25 was used. At this time, the value of Z was the same as the value of Y.

Furthermore, the discharge gas pressure during sputtering was set to 0.5 Pa, and the substrate temperature was kept constant at 600 ° C. The composition of the discharge gas at this time is a mixed gas of Ar gas and oxygen (O ₂ ) gas, and the ratio of O ₂ gas in the discharge gas is 0.5% to 50% with respect to Ar gas. Film formation was performed under conditions. Further, the composition of the discharge gas in the discharge space between the target and the substrate was measured using a mass filter, including during the formation of the PZT thin film 2. Further, the produced PZT thin film 2 was subjected to quantitative analysis of the film composition using an electron probe microanalysis (hereinafter referred to as EPMA) and evaluation of crystallinity by X-ray diffraction.

  Subsequently, a Pt film 3 as a second electrode film was formed on the PZT thin film 2 by sputtering using Ar gas at a discharge gas pressure of 0.5 Pa and at room temperature. FIG. 2B is a cross-sectional view showing a state in which the Pt film 3 is formed. In addition, it was confirmed that the PZT thin film 2 produced on the said conditions is spontaneously polarized so that it may face the upper direction of a board | substrate surface naturally, even if it does not apply an electric field especially and performs a polarization process.

  Next, as shown in FIG. 2C, a predetermined piezoelectric element shape was produced by performing photolithography and an etching process on the MgO substrate 15. As this shape, as shown in FIG. 1, the longitudinal direction is 2 mm, and the width direction is 0.5 mm.

  After processing into a predetermined shape in this way, the MgO substrate 15 is removed by etching as shown in FIG. 2D, whereby the piezoelectric element 10 having the shape shown in FIG. 1 is obtained.

  Next, a drive power source 5 was connected to the fabricated piezoelectric element 10 as shown in FIG. 1, and the displacement in the direction indicated by the arrow B was measured. The applied voltage was 10V. The amount of displacement is the value of displacement in the direction indicated by arrow B when a voltage of 10 V is applied. This displacement was measured using a laser Doppler vibrometer.

  FIG. 3 is a diagram showing the results of determining the relationship between the displacement amount of the piezoelectric element 10 and the oxygen partial pressure with respect to the degree of crystal orientation using a target having a Y = 0.25 composition. The horizontal axis represents the oxygen partial pressure with respect to the total pressure as a percentage, the left side of the vertical axis is the displacement, and the right side is the degree of crystal orientation.

  The degree of crystal orientation of the PZT thin film 2 was determined by an X-ray diffractometer. X-ray diffraction was measured for θ-2θ using a CuKα radiation source. The angle range of 2θ was 20 ° to 40 °. Since the tetragonal PZT thin film 2 is polarized in the (001) direction, the degree of crystal orientation was determined by the X-ray diffraction peak intensity ratio (001) / Σ (hkl). In the case of a material whose polarization is in the (001) direction, it is obtained by (001) / Σ (hkl), and when the polarization is in the (111) direction, it is obtained by (111) / Σ (hkl). Here, Σ (hkl) is derived from PZT when the upper and lower limits of 2θ are set in the minimum range in which (111) reflection can be measured from (001) reflection in θ-2θ measurement using a CuKα radiation source. It is the sum of the intensity of the reflection peaks. Hereinafter, the degree of crystal orientation is sometimes simply referred to as the degree of orientation.

  As can be seen from FIG. 3, the degree of orientation decreases when the oxygen partial pressure is 2% or less, but it is 60% even when the oxygen partial pressure is 0.5%. Further, when the oxygen partial pressure is 50%, the degree of orientation sharply decreases, but even in this case, the degree of orientation is 65%. When the oxygen partial pressure is in the range of 0.5% to 10%, the oxygen partial pressure is 1.5% and the degree of orientation is 95%. When the oxygen partial pressure is further increased, the degree of orientation gradually increases. Was 10% and the degree of orientation was 100%. When the oxygen partial pressure was in the range of 10% to 30%, the degree of orientation was 100%, the degree of orientation was 96% when the oxygen partial pressure was 40%, and the degree of orientation suddenly decreased at an oxygen partial pressure higher than that.

  On the other hand, the displacement increases rapidly as the oxygen partial pressure increases from 0.5% to 2%. However, when it exceeds 2%, the amount of displacement decreases. The degree of this decrease was found to have an inflection point, with the oxygen partial pressure varying around 10%.

  FIG. 4 shows the result of determining the relationship between the displacement amount of the piezoelectric element 10 due to the partial pressure of oxygen and the oxygen deficiency amount ratio (Y−Z) / (Y + 3) using a target of Y = 0.25 composition. FIG. The horizontal axis represents the oxygen partial pressure with respect to the total pressure in percent. The left side of the vertical axis is the displacement amount, and the right side is the oxygen deficiency ratio (Y−Z) / (Y + 3). FIG. 5 is a graph showing the relationship between the oxygen deficiency ratio (Y−Z) / (Y + 3) and the displacement.

  A method for obtaining the oxygen deficiency ratio will be described below. First, the composition of the ferroelectric thin film necessary for obtaining the oxygen deficiency ratio was measured by EPMA as described above. This analysis method is an analysis method for obtaining the composition of a sample by irradiating a sample surface with a very finely focused electron beam and measuring the wavelength and intensity of characteristic X-rays radiated from that portion with an X-ray spectrometer. .

Specifically, the quantitative analysis of the PZT thin film was performed as follows. That is, the X-ray intensity is first measured using a standard sample in which the concentration of each element of Pb, Zr, Ti and O is known. As an example, Pb will be described below. It is _assumed that the Pb concentration of the standard sample is W _Pbstd and the X-ray intensity of the sample is I _Pbstd . Next, the X-ray intensity of Pb when measuring a PZT thin film whose concentration is unknown is assumed to be _IPb . When linear approximation is performed from these data, the concentration W _Pb of Pb of the PZT thin film whose concentration is unknown can be obtained from the following equation.

W _Pb = W _Pbstd × I _Pb / I _Pbstd
However, I _Pb and I _Pbstd are X-ray intensities per unit current after dead time correction and background correction.

By the same method, the concentrations W _Zr , W _Ti and W 2 of _Zr , _Ti and _O are obtained, respectively.

Next, a ZAF correction coefficient is calculated. Z is atomic number correction, and is obtained by calculating the value of Duncum-Reed by the method of least squares. A is an absorption correction and is calculated using the Philbert equation. F is fluorescence correction, and is obtained using the Reed equation. From the values obtained by normalizing W _Pb , W _Zr , W _Ti and W 2 _O , the first ZAF correction coefficients Z, A and F of the respective elements are calculated and multiplied to obtain the corrected concentration. The ZAF correction coefficient is calculated again using the density value thus obtained. Using this correction coefficient, a further corrected density is obtained. Thus, these were repeated until the calculation error became 0.001%, and the quantitative value was obtained.

  The apparatus used for the analysis is a wavelength dispersion type EPMA (JXA-8900R manufactured by JEOL Ltd.). A sample processed into a square shape having a size of about 5 mm was used. The sample was attached to a sample table with a carbon paste to obtain electrical conduction, and the surface was coated with carbon.

  In actual measurement, first, a total qualitative analysis is performed on the sample in order to confirm the film thickness and to check for the presence of impurities. Thereby, it is also confirmed whether an electron beam has penetrated to the ground. Next, the PZT of the standard sample is measured. Thereafter, the value of the standard sample is read and the sample is quantitatively analyzed. The analysis conditions at this time are an acceleration voltage of 15 kV, an irradiation current of 70 mA, and a beam diameter of 10 μm. The presence or absence of measurement abnormality is confirmed. If the measurement is normal, the measured data is normalized to obtain a measurement result. By the above measuring method, quantitative values of Pb, Zr, Ti and O are obtained.

  Oxygen deficiency ratio (Y−Z) / (Y + 3) was defined as the ratio of oxygen deficiency in the PZT thin film 2 when Pb was divalent and Zr and Ti were tetravalent. That is, if the oxidation of Pb occurs completely stoichiometrically, the amount of oxygen (O) at that time is Y + 1, which is the same as Pb, and if the oxidation of Zr occurs similarly stoichiometrically, At that time, the amount of oxygen (O) is 2X, which is twice that of Zr, and if oxidation of Ti occurs similarly, the amount of oxygen (O) is 2 (1-X), which is twice that of Ti. Therefore, in the stoichiometric composition state, the total oxygen amount is (Y + 1) + 2X + 2 (1−X) = (Y + 3).

On the other hand, since the actual amount of oxygen in the fabricated PZT thin film 2 is (3 + Z), the shortage of oxygen is (Y + 3) − (3 + Z) = (Y−Z). Since the total oxygen amount in the stoichiometric composition is (Y + 3), the ratio of oxygen deficiency is (Y−Z) / (Y + 3), which is the ratio of both. That is, (Y−Z) / (Y + 3) represents the oxygen deficiency ratio. The values of X, Y and Z can be easily obtained by calculating based on these values since W _Pb , W _Zr , W _Ti and W 2 _O are obtained from the above quantitative analysis results by EPMA. .

  As shown in FIG. 4, it was found that when the oxygen partial pressure was 1% or less, the oxygen deficiency ratio (Y−Z) / (Y + 3) rapidly increased as the oxygen partial pressure decreased. That is, it was found that a large amount of oxygen deficiency occurs in the PZT thin film 2 when the oxygen partial pressure is 1% or less. When the oxygen partial pressure is greater than 1%, the oxygen deficiency ratio gradually decreases, the oxygen partial pressure is 10%, and the oxygen deficiency ratio is 0.2% (0.002). A PZT thin film 2 having a stoichiometric composition is obtained.

  Further, as can be seen from FIG. 4, the oxygen partial pressure of 2% at which the oxygen deficiency ratio is 5% (0.05) is changed from the oxygen partial pressure of 10% at which the oxygen deficiency ratio is 0.2% (0.002). Up to this point, the displacement amount tends to increase almost linearly as the oxygen deficiency ratio increases. However, when the oxygen deficiency amount ratio is greater than 5% (0.05), the displacement amount is decreased, and no correlation with the oxygen deficiency amount ratio is observed in this region. This is because the degree of orientation decreases as shown in FIG.

  FIG. 5 shows the relationship between the oxygen deficiency ratio (Y−Z) / (Y + 3) and the displacement. The amount of displacement shows the maximum value when the oxygen deficiency ratio is about 5% (0.05). When the oxygen deficiency ratio is less than 5% (0.05), the displacement amount gradually decreases. On the other hand, even when the oxygen deficiency ratio is 5% (0.05) or more, the decrease similarly occurs. However, when the oxygen deficiency ratio is in the vicinity of 10% (0.1), the displacement amount has an inflection point. It can be seen.

  From the above results, it has been found that it is effective to cause oxygen vacancies to some extent in the PZT thin film 2 in order to increase the displacement amount of the piezoelectric element 10. The upper limit of the oxygen deficiency ratio is 0.1 when the degree of orientation of the PZT thin film 2 is 70% or more. It can be seen from FIG. 4 that the displacement amount larger than the displacement amount when the degree of orientation is 100% and there is no oxygen deficiency is 10% (0.1) or less as the oxygen deficiency ratio. by. The oxygen partial pressure at this time needs to be 1% or more and less than 10%.

  Furthermore, if the oxygen deficiency ratio is in the range of 2% (0.02) to 7% (0.07), as shown in FIG. Even if the variation occurs, the variation of the displacement amount can be made relatively small. This is desirable because the manufacturing yield can be improved. Furthermore, if the oxygen deficiency amount ratio is 2% (0.02) or more and 5% (0.05) or less, the variation of the displacement amount with respect to the oxygen deficiency amount ratio can be further reduced. Therefore, it is more desirable because the manufacturing yield can be further improved.

  The oxygen partial pressure when the oxygen deficiency ratio is in the range of 2% (0.02) to 7% (0.07) may be set to a range of 1.5% or more and less than 5%. is necessary.

In FIG. 6, when the composition is represented by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1), X = 0.58 is constant, Oxygen partial pressure in the discharge gas and displacement of the piezoelectric element 10 when the PZT thin film 2 is produced using three types of targets having compositions of Y = 0, Y = 0.25, and Y = 1. The relationship with quantity is shown.

  When a target with Y = 0 is used, the peak value of the displacement amount is in the range where the oxygen partial pressure is 10% to 20%, and the displacement amount is small as a whole. Since Y = 0, the PZT thin film produced by sputtering using this target is in a Pb-deficient state.

  When using a Y = 1 target, it was found that the oxygen partial pressure had a local displacement peak in the vicinity of 1%.

  On the other hand, it was found that when a target with Y = 0.25 was used, the range in which a large amount of displacement was obtained was wide, and the PZT thin film 2 could be manufactured with a high yield.

As can be seen from FIG. 6, as the value of Y indicating the Pb composition in the target increases from 0, the oxygen partial pressure value indicating the displacement peak tends to shift to a smaller value. Although not shown, the relationship with the amount of displacement was examined using a target in which the value of Y was further varied. As a result, when the range is 0 <Y <1, it is found that by forming the film with the oxygen partial pressure in the range of 1% to 10%, the piezoelectric characteristics are good and the mass productivity and the yield can be improved. It was done. The oxygen partial pressure may be controlled by controlling the ratio of the introduced argon (Ar) gas and oxygen (O ₂ ) gas while analyzing the discharge gas with a mass filter during sputtering. Alternatively, when the target is Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} and Z≈0, the flow rate ratio of Ar and O ₂ introduced as the discharge gas is set to the above range. Even if set and introduced, the same piezoelectric thin film can be obtained.

In the present embodiment, when expressed by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1), X = 0.58 is constant, and Z is A target having the same value as Y was used. However, the value of Z, which is the oxygen composition of the target, is not limited to the same value as Y, which is the Pb composition, and may be set individually. That is, if it is in the range of -3 ≦ Z ≦ Y, the oxygen content in the discharge gas at the time of sputtering is within the above range, and a piezoelectric thin film having good piezoelectric characteristics is produced if the film formation rate is appropriately controlled. can do.

  In this embodiment, a (100) -oriented MgO substrate is used as the substrate, but the present invention is not limited to this. For example, a single crystal silicon substrate, a single crystal strontium titanate substrate, a sapphire substrate, a sintered alumina substrate, a zirconia substrate, or the like can be used. If spontaneous polarization does not occur when these substrates are used, polarization treatment may be performed after the oxide piezoelectric thin film is formed.

  Furthermore, although the Pt film is used as the first electrode film in the present embodiment, the present invention is not limited to this. For example, gold (Au), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), or an oxide thereof can be used similarly.

  In this embodiment, a Pt film is used as the second electrode film, but the present invention is not limited to this. For example, the same material as the first electrode film can be used. Furthermore, any metal material such as aluminum (Al), copper (Cu), nickel (Ni) can be used without any particular limitation.

  In this embodiment, the piezoelectric element is processed by photolithography and an etching process, but the present invention is not limited to this. For example, the predetermined shape may be produced by sputtering or vapor deposition using a mask.

(Second Embodiment)
In this embodiment, a case will be described in which an actuator made of a piezoelectric element manufactured by the method described in the first embodiment is manufactured and this actuator is used for positioning a magnetic head of a magnetic disk device. FIG. 7 is a schematic diagram of a device configuration in which the piezoelectric element of the present embodiment is used for positioning a magnetic head of a magnetic disk device. This magnetic disk apparatus is characterized by a two-stage actuator configuration in which an actuator made of a piezoelectric element of the present invention is added to an actuator made of a conventional voice coil motor. The magnetic head support mechanism 100 includes a suspension 104 having a relatively low rigidity, a leaf spring portion 105, an arm 106 having a relatively high rigidity, a flexure 103, a slider 102 attached to the surface facing the disk 200 on the flexure 103, and A magnetic head (not shown) mounted on the slider 102 and a piezoelectric element 108 bonded and fixed on the flexure 103 are configured.

  The suspension 104 is designed to have relatively low rigidity, and the other end constitutes a leaf spring portion 105, and the leaf spring portion 105 is fixed to the arm 106. A voice coil motor is constituted by a voice coil 112 attached to the arm 106 and a magnet (not shown). The magnetic head support mechanism 100 can be rotated within a predetermined angle range in a direction parallel to the surface of the disk 200 by the voice coil motor.

  Further, the piezoelectric element 108 is driven in order to accurately position the magnetic head mounted on the slider 102 at a predetermined track position of the disk 200. That is, the magnetic head support mechanism 100 has a two-stage actuator configuration in which the positioning is roughly performed by a voice coil motor and fine adjustment is performed by the piezoelectric element 108.

  The operation of this magnetic disk device will be described. The disk 200 is rotated at a predetermined rotation speed by the rotation driving means 220. During recording / reproduction of the magnetic disk device, the slider 102 floats with a certain flying height by the balance between the levitation force caused by the air flow generated by the rotation of the disk 200 and the urging force that presses the slider 102 against the disk 200 surface side. The magnetic head performs recording and reproduction in this constant flying state. Recording and reproduction are performed in such a floating state. In order to position the magnetic head at a predetermined track position, the arm 106 is rotated around the bearing 110 by a voice coil motor. In the conventional magnetic disk apparatus, positioning is performed only by this voice coil motor, but in the magnetic disk apparatus of the present embodiment, positioning with high accuracy is further performed by the piezoelectric element 108.

  FIG. 8 shows the shape of the vicinity of the piezoelectric element 108. FIG. 8A is a plan view thereof, and FIG. 8B is a cross-sectional view taken along line XX shown in FIG. A pair of piezoelectric elements 108A and 108B are bonded and fixed on the flexure 103 with an adhesive layer 107 at positions symmetrical to the center line Y-Y line in the longitudinal direction of the suspension. Each of the piezoelectric elements 108A and 108B has a symmetrical shape with respect to the YY line, and the cross-sectional structure thereof is also the same. That is, the piezoelectric elements 108A and 108B are formed by the first electrode film 1081 and the second electrode film 1083 so as to sandwich the PZT thin film 1082. Furthermore, an insulating protective resin film may be formed on the surface of these piezoelectric elements 108A and 108B. The first electrode film 1081 and the second electrode film 1083 of each of the piezoelectric elements 108A and 108B are connected to the electrode pad 103A of the flexure 103 and the wire lead 109. From the electrode pad 103A, a piezoelectric electrode wiring 103B connected to a control unit (not shown) of the magnetic disk device is formed on the flexure 103. Also, a magnetic head electrode wiring 103C for connecting a magnetic head mounted on the slider 102 and a control unit (not shown) of the magnetic disk device is formed on the flexure 103 at the center of the pair of piezoelectric elements 108A and 108B. Is formed.

  A voltage of 10 V was applied to the piezoelectric element 108 in the magnetic head support mechanism 100 having this configuration to measure the displacement of the magnetic head (not shown). As a result, in the case of a PZT thin film in which the oxygen deficiency ratio is 0 <(Y−Z) / (Y + 3) ≦ 0.1, the displacement is twice or more larger than that of a piezoelectric element using a conventional PZT thin film. It was found that the amount could be generated. Therefore, compared with the conventional piezoelectric element, fine positioning can be performed in a larger range, and a magnetic disk device with a higher recording density can be realized.

  In the piezoelectric elements 108A and 108B shown in FIG. 8, the PZT thin film 1082 is sandwiched between the first electrode film 1081 and the second electrode film 1083, and only one PZT thin film 1082 is provided. A structure in which a plurality of PZT thin films are laminated by bonding the films having this configuration with an adhesive or the like may be employed. By laminating, a larger displacement driving force can be obtained.

  Note that in the case of the PZT thin film in this embodiment, the crystal structure is tetragonal and has (001) orientation. This is because the polarization is oriented in the (001) direction in tetragonal PZT. This is because the orientation to (001) is advantageous in terms of piezoelectric characteristics. In the case of a rhombohedral PZT thin film, the polarization is oriented in the (111) direction. In this case, it is advantageous in terms of piezoelectric characteristics if the degree of orientation of (111) is kept high.

In the present embodiment, the case where X = 0.58 in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} has been described. However, the present invention is not particularly limited to this. Absent. In PZT, the crystal structure depends on X, and the composition of the value of X that is near the boundary between the tetragonal system and the rhombohedral system is called the MPB (morphotropic phase boundary) composition, and the piezoelectricity becomes high It has been known. If a composition in the vicinity is used, not only X = 0.58 but also a piezoelectric element having high piezoelectricity can be obtained. Note that the value of X, which is the boundary between the tetragonal system and the rhombohedral system, depends on the film formation method, the amount of additive, and the like, and may be adjusted as appropriate.

  In this embodiment, PZT has been described as the material for the piezoelectric thin film. However, if necessary, an additive element may be added to adjust the material characteristics. In that case, the oxygen deficiency may be calculated in consideration of the amount of additive and its valence. The elements as additive elements and their valences are as follows. Group 1 typical elements are monovalent, Group 2 typical elements, Mn, Ni, Cu, Zn, Sm, Eu, Yb are divalent, Sc, Y, Cr, B, Al, Ga, In, Sb, Bi, La, Nd, Pm, Gd, Dy, Ho, Er, Tm, and Lu are trivalent, and Hf, Ir, Si, Ge, Sn, Ce, Pr, and Tb are tetravalent.

  In this embodiment, the PZT thin film is directly formed on the Pt film. However, in order to improve the crystallinity and crystal orientation of the PZT thin film, a base film is formed on the Pt film, and the PZT thin film is formed thereon. May be formed.

  In this embodiment, heat treatment is not performed after film formation, but heat treatment may be performed as necessary to improve the crystallinity and crystal orientation of the PZT thin film.

  Further, although sputter film formation is performed in the present embodiment, the present invention is not limited to sputter film formation, and a PZT thin film manufactured by laser ablation film formation is also piezoelectric by forming a film having oxygen vacancies. Has been confirmed to improve. Furthermore, the present invention is not limited to the PZT thin film, and the effect of the present invention can be achieved as long as it is an oxide piezoelectric thin film.

  In the piezoelectric element of the present invention, the crystal structure of the piezoelectric thin film may be a perovskite type tetragonal system, the orientation parallel to the polarization axis may be a (001) plane orientation, or the crystal structure of the piezoelectric thin film May be a perovskite rhombohedral system, and the orientation parallel to the polarization axis may be the (111) orientation. Accordingly, a piezoelectric element manufactured using a tetragonal PZT thin film or a rhombohedral PZT thin film as the piezoelectric material has large piezoelectric characteristics.

In addition, the piezoelectric element of the present invention may include a part of Pb in the general formula Pb _{1 + Y} (Zr _x Ti _1-x ) O _{3 + Z} (where 0 <X <1) And at least one element selected from manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), samarium (Sm), europium (Eu) and ytterbium (Yb). In the composite oxide piezoelectric thin film to which one or more kinds of such elements are added, the piezoelectric characteristics can be further improved by making the amount of oxygen deficiency larger than 0% and smaller than 10%.

The piezoelectric element of the present invention is at least one selected from Ti and Zr in the general formula Pb _{1 + Y} (Zr _x Ti _1-x ) O _{3 + Z} (where 0 <X <1). A part of the element was selected from hafnium (Hf), iridium (Ir), silicon (Si), germanium (Ge), tin (Sn), cerium (Ce), praseodymium (Pr) and terbium (Tb) It may be replaced with at least one element. In a composite oxide piezoelectric thin film in which a part of at least one element selected from Ti and Zr is substituted with such an element, if the oxygen deficiency is larger than 0% and smaller than 10%, the piezoelectric characteristics are further improved. Can be improved.

In addition, the piezoelectric element of the present invention has at least one selected from Pb, Ti and Zr in the general formula Pb _{1 + Y} (Zr _x Ti _1-x ) O _{3 + Z} (where 0 <X <1). A part of one kind of element is a monovalent one-genus typical element, scandium (Sc), yttrium (Y), chromium (Cr), boron (B), aluminum (Al), gallium (Ga), indium (In ), Antimony (Sb), bismuth (Bi), lanthanum (La), neodymium (Nd), promethium (Pm), gadolinium (Gd), dysprodium (Dy), holmium (Ho), erbium (Er), thulium ( It may be replaced with at least one element selected from Tm) and lutetium (Lu). In a composite oxide piezoelectric thin film in which a part of at least one element selected from Pb, Ti and Zr is substituted with such an element, if the amount of oxygen deficiency is larger than 0% and smaller than 10%, the piezoelectricity is further increased. The characteristics can be improved.

  In the embodiment of the present invention, the method for producing a piezoelectric thin film by sputtering has been described. However, the present invention is not limited to this. For example, you may produce by the laser ablation method. This enables crystal growth of the oxide piezoelectric thin film while precisely controlling the amount of oxygen vacancies in a gas atmosphere controlled with high precision, and the distribution of oxygen vacancies in the film can be made uniform. . For example, even when a piezoelectric material is formed by a powder sintering method, oxygen deficiency occurs if fired in a low oxygen atmosphere. In this case, however, oxygen deficiency is likely to be localized, which reduces reliability. End up. In the case of chemical vapor deposition (CVD), unlike the sputtering method or laser ablation method, a film is formed by oxidation and decomposition of the reaction gas, so that the piezoelectric material has good piezoelectric characteristics at a low oxygen partial pressure. It is relatively difficult to form a body thin film.

  On the other hand, the oxide piezoelectric thin film produced by sputtering or laser ablation method has a predetermined amount of oxygen deficiency uniformly in the film, thereby obtaining a piezoelectric thin film with large piezoelectric characteristics and high reliability. Can do. When sputtering is performed with the oxygen partial pressure exceeding 10%, oxygen vacancies do not occur and the film formation rate cannot be increased. On the other hand, when the oxygen partial pressure is 1% or less, the ratio of crystals parallel to the polarization axis is lowered, and the piezoelectric characteristics are not improved. That is, in order to obtain the necessary piezoelectric characteristics, the degree of crystal orientation needs to be 70% or more. For this purpose, the oxygen partial pressure is required to be 1% or more. Further, since sputtering is performed at such a relatively low oxygen partial pressure, the film formation rate can be increased and the mass productivity can be improved.

  Furthermore, in the sputtering method or the laser ablation method, the ratio of the oxygen gas introduction flow rate to the inert gas introduction flow rate may be 0.01 or more and less than 0.1 as the gas introduction flow rate into the vacuum apparatus. As a result, an oxide piezoelectric thin film having a predetermined oxygen deficiency ratio can be obtained even under relatively low-pressure discharge gas pressure conditions, high-speed film formation is possible, and mass productivity can be greatly improved.

  The piezoelectric element and the manufacturing method thereof according to the present invention can obtain a piezoelectric element having larger piezoelectric characteristics than before by using an oxide piezoelectric thin film having oxygen vacancies, and can form a film at high speed. Therefore, it is possible to improve the characteristics of the piezoelectric element and improve the mass productivity, and it can be applied to applications such as functional electronic parts such as actuators and sensors.

The perspective view of the piezoelectric element in the 1st Embodiment of this invention Sectional drawing of the main processes of the manufacturing method of the piezoelectric element of the embodiment The figure which shows the result of having calculated | required the relationship with the oxygen partial pressure with respect to the displacement amount and crystal orientation degree of the piezoelectric element produced using the target of Y = 0.25 composition in the same embodiment. The figure which shows the result of having calculated | required the relationship with the oxygen partial pressure with respect to the displacement amount and oxygen deficiency amount ratio of the piezoelectric element produced using the target of Y = 0.25 composition in the same embodiment. The figure which calculated | required the relationship between the oxygen deficiency amount ratio and displacement amount of the piezoelectric element of the same embodiment The figure which shows the relationship between the displacement of a piezoelectric element produced by changing the target composition and the oxygen partial pressure in the same embodiment The figure which shows the example which used the piezoelectric material element for the magnetic head positioning of a magnetic disc apparatus as the 2nd Embodiment of this invention (A) is a plan view showing the shape of the vicinity of the piezoelectric element of the magnetic disk apparatus of the same embodiment (b) is a cross-sectional view taken along line XX shown in (a)

Explanation of symbols

1,1081 First electrode film (Pt film)
2,1082 Oxide piezoelectric thin film (PZT thin film)
3,1083 Second electrode film (Pt film)
DESCRIPTION OF SYMBOLS 5 Drive power supply 10,108,108A, 108B Piezoelectric element 15 MgO board | substrate 100 Magnetic head support mechanism 102 Slider 103 Flexure 103A Electrode pad 103B Piezoelectric electrode wiring 103C Magnetic head electrode wiring 104 Suspension 105 Leaf spring part 106 Arm 107 Adhesive layer 109 Wire lead 110 Bearing portion 112 Voice coil 200 Disc 220 Rotation drive means

Claims (14)

A first electrode film, a second electrode film, and a piezoelectric thin film sandwiched between the first electrode film and the second electrode film,
The piezoelectric element, wherein the piezoelectric thin film is an oxide piezoelectric thin film having an oxygen deficiency of greater than 0% and 10% or less with respect to the stoichiometric composition. The piezoelectric thin film is lead zirconate titanate represented by the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1), and the piezoelectric thin film 2. The piezoelectric according to claim 1, wherein 0 <(Y−Z) / (Y + 3) ≦ 0.1 when the oxygen deficiency ratio is expressed as (Y−Z) / (Y + 3). Body element. 3. The piezoelectric element according to claim 2, wherein the piezoelectric thin film has a crystal orientation degree of 70% or more in an orientation parallel to a polarization axis thereof. 4. The piezoelectric element according to claim 3, wherein the piezoelectric thin film has a perovskite-type tetragonal crystal structure and is oriented in the (001) direction. 4. The piezoelectric element according to claim 3, wherein the piezoelectric thin film has a perovskite rhombohedral system and has a crystal orientation in a (111) direction. 5. A part of Pb in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1) is substituted with two group typical elements, manganese (Mn), nickel (Ni) 3. The composition according to claim 2, comprising at least one element selected from copper (Cu), zinc (Zn), samarium (Sm), europium (Eu) and ytterbium (Yb). Piezoelectric element. A part of at least one element selected from Ti and Zr in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1) is substituted with hafnium (Hf ), Iridium (Ir), silicon (Si), germanium (Ge), tin (Sn), cerium (Ce), praseodymium (Pr) and at least one element selected from terbium (Tb) The piezoelectric element according to claim 2, wherein: A part of at least one element selected from Pb, Ti and Zr in the general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1) is 1 Valent group 1 typical elements, scandium (Sc), yttrium (Y), chromium (Cr), boron (B), aluminum (Al), gallium (Ga), indium (In), antimony (Sb), bismuth (Bi) ), Lanthanum (La), neodymium (Nd), promethium (Pm), gadolinium (Gd), dysprodium (Dy), holmium (Ho), erbium (Er), thulium (Tm) and lutetium (Lu) The piezoelectric element according to claim 2, wherein the piezoelectric element is configured to be replaced with at least one kind of element. 2. The piezoelectric element according to claim 1, wherein the piezoelectric thin film is a thin film produced by a sputtering method or a laser ablation method. Forming a first electrode film on the substrate;
On the first electrode film, it is represented by the general formula A _{1 + Y} BO _{3 + Z} (where A and B represent elements), and the degree of crystal orientation in the direction parallel to the polarization axis is 70% or more. A process of forming an oxide piezoelectric thin film in a range where the oxygen partial pressure in the vacuum apparatus during film formation is 1% or more and less than 10% with respect to the total pressure when forming a thin oxide film by sputtering or laser ablation When,
Forming a second electrode film on the oxide piezoelectric thin film;
A method of manufacturing a piezoelectric element, comprising: processing the first electrode film, the oxide piezoelectric thin film, and the second electrode film into a preset pattern shape. The oxide piezoelectric thin film has the general formula A _{1 + Y} BO _{3 + Z} (where A and B represent elements), where A is lead (Pb), and B is zirconium (Zr) and titanium (Ti 11. The method for manufacturing a piezoelectric element according to claim 10, wherein the lead zirconate titanate comprises a perovskite tetragonal system and the crystal orientation is in the (001) direction. The oxide piezoelectric thin film has the general formula A _{1 + Y} BO _{3 + Z} (where A and B represent elements), where A is lead (Pb), and B is zirconium (Zr) and titanium (Ti 11. The method for manufacturing a piezoelectric element according to claim 10, wherein the crystal structure is perovskite rhombohedral and the crystal orientation is in the (111) direction. . In the step of forming the oxide piezoelectric thin film by the sputtering method or the laser ablation method, a general formula Pb _{1 + Y} (Zr _X Ti _1-X ) O _{3 + Z} (where 0 <X <1) is used as a film forming source. 13. The method for manufacturing a piezoelectric element according to claim 11, wherein a target having a composition of 0 <Y <1 and −3 ≦ Z ≦ Y is used. In the step of forming the oxide piezoelectric thin film by the sputtering method or the laser ablation method, the ratio of the oxygen gas introduction flow rate to the total gas introduction flow rate is 0.01 or more and less than 0.1 as the gas introduction flow rate into the vacuum apparatus The method for manufacturing a piezoelectric element according to claim 13.

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