JP2009128520A - Display device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel integrated display device wherein a variance in the characteristics of a photosensor is reduced. <P>SOLUTION: The display device includes a plurality of pixel sections, and each of the plurality of the pixel sections includes a pixel electrode, a transistor for changing over ON/OFF of the voltage application to the pixel electrode and the photosensor for receiving the light made incident on the inside of the pixel section. The transistor has a source region, drain region, and channel region, formed of polysilicon. The photosensor has a P type amorphous silicon region, and an N type amorphous silicon region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device and a manufacturing method thereof.

  A TFT substrate, which is a thin film semiconductor device having a thin film transistor (TFT), is used as a driving substrate for driving liquid crystal in an active matrix liquid crystal display device. 2. Description of the Related Art In recent years, light-weight and highly integrated displays have been increasingly used in small and medium-sized displays mounted on mobile phones and PDAs (Personal Digital Assistants). As part of this, a technology for forming a circuit of a display device and a circuit of a touch panel on the same substrate in a module equipped with a touch panel has been proposed (see Patent Document 1).

  According to Patent Literature 1, an optical touch panel is integrated with a display device by forming a light receiving element such as a phototransistor on a TFT substrate and configuring a light receiving circuit. The light receiving element is formed by the same process as that of the TFT, and can be reduced in weight and performance without causing an increase in cost and man-hours. Therefore, the added value can be efficiently increased.

  FIG. 11 shows a touch panel integrated display device 700. By detecting the contact position of a finger or the like by comparing the amount of received light, it functions as a touch panel.

  A TFT area 703 including a TFT for switching ON / OFF of voltage application to the pixel electrode is provided on a TFT substrate 701 of the display device 700, and a light receiving element 711 is provided therein. A light shielding layer 712 is provided between the TFT substrate 701 and the light receiving element 711. On the TFT area 703, a liquid crystal layer 704, a color filter 705, and a counter substrate 702 are provided. Although other polarizing plates are provided, they are not shown here for the sake of simplicity. An image is displayed when light emitted from the light source 706 passes through the above-described components. When operating as a touch panel (during coordinate detection operation), when a pen or a finger is touched on the display surface and when it is not touched, the light receiving element 711 immediately below the contact position receives light. Since the intensity of the light to be changed changes, the coordinates of the contact position can be detected from the change in the intensity of the light.

  In such a touch panel integrated display device, it is desirable to reduce variations in characteristics of photosensors such as photodiodes.

  The TFT is formed using poly-Si (polysilicon). For this reason, the photodiode formed by the same process as the TFT is also formed from poly-Si. However, when a photodiode is formed using poly-Si, the characteristics of the photodiode vary due to crystal grain boundaries and the like.

  Although it is conceivable to form a TFT using amorphous Si (amorphous silicon), the mobility of electrons in amorphous Si is smaller than that in poly-Si, and in this case, the performance of the TFT is lowered, which is not desirable. .

  Incidentally, Patent Document 2 discloses a technique for forming a poly-Si layer partly made of amorphous Si.

In the Si crystallization process of the TFT manufacturing method disclosed in Patent Document 2, the amorphous Si layer on the glass substrate is irradiated with laser light from the display surface side. Prior to laser light irradiation, a gate electrode is formed in advance on the amorphous Si layer, and the gate electrode shields the laser light, so that a region (channel region) immediately below the gate electrode in the amorphous Si layer is a crystal. Amorphous Si remains as it is without conversion. Other regions are crystallized into poly-Si. By this method, a TFT in which the source region and the drain region are poly-Si and the channel region is amorphous Si is formed.
JP 2006-79589 A JP-A-9-191114

  However, in the above manufacturing method, regions other than the channel region in the amorphous Si layer are crystallized to become poly-Si. For this reason, when an attempt is made to manufacture a touch panel integrated display device using the above manufacturing method, the photodiode region is made of poly-Si, so that the characteristics of the photodiode vary.

  The present invention has been made in view of the above problems, and provides a touch panel integrated display device in which TFT performance is maintained high and variation in characteristics of a photosensor is small, and a method for manufacturing the same.

  The display device of the present invention is a display device including a plurality of pixel portions, each of the plurality of pixel portions including a pixel electrode, a transistor that switches ON / OFF of voltage application to the pixel electrode, A photosensor that receives light incident on the pixel portion, and the transistor has a source region, a drain region, and a channel region formed of polysilicon, and the photosensor includes a P-type amorphous silicon region and an N-type region And an amorphous silicon region.

  According to an embodiment, the display device further includes a light source that emits light, and each of the plurality of pixel units further includes a light shielding layer disposed between the photosensor and the light source, The bottom area of the light shielding layer is wider than the bottom area of the photosensor.

  According to an embodiment, the end of the light shielding layer is at a position extending a predetermined length from the end of the photosensor, and the predetermined length is longer than the length of the polysilicon crystal grains.

  According to an embodiment, the end portion of the light shielding layer is at a position extending 2 μm or more from the end portion of the photosensor.

  The display device manufacturing method of the present invention includes a step of forming a light shielding layer at a position on one surface side of a glass substrate, and a step of forming an amorphous silicon layer at a position on the opposite side of the light shielding layer from the glass substrate. Irradiating the amorphous silicon layer with light through the glass substrate to crystallize a part of the amorphous silicon layer, and a polysilicon region formed by the crystallization and the amorphous silicon region. A step of separating, a step of forming a gate electrode of the transistor at a position opposite to the glass substrate of the polysilicon region, and ion implantation into the polysilicon region to form a source region and a drain region of the transistor And forming a P-type amorphous silicon region and an N-type anode by implanting ions into the amorphous silicon region. Characterized in that it comprises a step of forming a photo sensor and a Rufasu silicon region.

  The display device of the present invention is a display device including a plurality of pixel portions, each of the plurality of pixel portions including a first and a second transistor and an organic light emitting diode, The second transistor switches between an ON state and an OFF state, the second transistor changes a voltage supplied to the organic light emitting diode in accordance with switching between the ON state and the OFF state, and the first transistor includes polysilicon The second transistor has a source region, a drain region, and a channel region formed of amorphous silicon.

  According to an embodiment, the display device further includes a substrate on which the first and second transistors are formed, and each of the plurality of pixel units is disposed between the second transistor and the substrate. The bottom area of the light shielding layer is larger than the bottom area of the second transistor.

  According to an embodiment, the end of the light shielding layer is located at a position extending a predetermined length from the end of the second transistor, and the predetermined length is longer than the length of the polysilicon crystal grains. .

  According to an embodiment, the end portion of the light shielding layer is at a position extending 2 μm or more from the end portion of the second transistor.

  The display device manufacturing method of the present invention includes a step of forming a light shielding layer at a position on one surface side of a glass substrate, and a step of forming an amorphous silicon layer at a position on the opposite side of the light shielding layer from the glass substrate. Irradiating the amorphous silicon layer with light through the glass substrate to crystallize a part of the amorphous silicon layer, and a polysilicon region formed by the crystallization and the amorphous silicon region. A step of separating, a step of forming a gate electrode of the first transistor at a position opposite to the glass substrate of the polysilicon region, and a position of the amorphous silicon region opposite to the glass substrate. Forming a two-transistor gate electrode, and implanting ions into the polysilicon region and the amorphous silicon region; Characterized in that it comprises a step of forming a source region and a drain region of each of the first and second transistors.

  According to the present invention, the transistor includes a source region, a drain region, and a channel region formed of polysilicon, and the photosensor includes P-type amorphous silicon and N-type amorphous silicon. Accordingly, it is possible to provide a touch panel integrated display device in which variation in characteristics of the photosensor is small while maintaining high performance of the transistor.

  Moreover, in the manufacturing method of this invention, light is irradiated to an amorphous silicon layer from the glass substrate side, and a part of amorphous silicon layer is crystallized. At this time, since the laser light is shielded by the light shielding layer provided between the glass substrate and the photosensor region, the photosensor region is maintained as amorphous silicon. By forming the photosensor from this amorphous silicon, variation in characteristics of the photosensor can be reduced. Further, the transistor region is crystallized to become polysilicon, and by forming a transistor from this polysilicon, good transistor characteristics can be obtained. In addition, by using the light shielding layer as a masking layer in the photosensor region, a separate step of forming a masking layer becomes unnecessary, and the number of manufacturing steps can be reduced.

  According to an embodiment of the present invention, the end portion of the light shielding layer is located at a position extending a predetermined length from the end portion of the photosensor, and the predetermined length is greater than the length of the crystal grains of polysilicon. Too long. For example, the end portion of the light shielding layer is located at a position extending 2 μm or more from the end portion of the photosensor. As a result, even if the poly-Si crystal grains formed near the edge of the light shielding layer (that is, the boundary between amorphous silicon and polysilicon) shift to the photo sensor region side, the photo sensor region remains amorphous silicon. Can do.

  Further, according to the present invention, the first transistor switches between the ON state and the OFF state of the second transistor, and the second transistor changes the voltage supplied to the organic light emitting diode according to the switching between the ON state and the OFF state. In the organic EL display device, the first transistor has a source region, a drain region, and a channel region formed of polysilicon, and the second transistor has a source region, a drain region, and a channel region formed of amorphous silicon. . Accordingly, it is possible to provide an organic EL display device in which the characteristics of the second transistor are small while maintaining the performance of the first transistor high.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a liquid crystal display device 100 according to a first embodiment of the present invention. The liquid crystal display device 100 is a touch panel integrated display device that functions as a touch panel in addition to an image display function.

  The liquid crystal display device 100 includes a liquid crystal display panel 110, a light source 120, a control unit 131, and a detection unit 132. The control unit 131 controls operations of the liquid crystal display panel 110 and the light source 120. When the detection unit 132 operates as a touch panel (coordinate detection operation), the detection unit 132 detects a position touched by a contact object (such as a pen or a finger) on the display surface based on the intensity of received light.

  FIG. 2 shows the liquid crystal display panel 110. The liquid crystal display panel 110 includes a plurality of pixel portions 150, a plurality of gate lines 106, a plurality of source lines 107, and a plurality of signal lines 108. A gate line 106, a source line 107, and a signal line 108 are provided on a substrate (not shown) in a lattice shape. The source lines 107 and the signal lines 108 are alternately provided in parallel with each other. The gate lines 106 are arranged in a direction crossing the source line 107 and the signal line 108. A pixel portion 150 is disposed at each intersection of the gate line 106 and the source line 107.

  Each pixel unit 150 includes a liquid crystal cell 160 and a photosensor 102. The liquid crystal cell 160 displays an image by transmitting at least part of the light from the light source 120 during the image display operation. Also, during the coordinate detection operation, it plays the role of illuminating the contact object with the transmitted light. The photosensor 102 is, for example, a photodiode, and receives light incident on the pixel portion (reflected light and external light obtained by irradiating the contact object with light output from the liquid crystal cell 160).

  The liquid crystal cell 160 includes a thin film transistor (TFT) 101 that is a switching element and a pixel capacitor 105. The gate line 106 is connected to the gate electrode of the TFT 101, and the source line 107 is connected to the source electrode of the TFT 101. The pixel capacitor 105 is composed of, for example, a liquid crystal capacitor and an auxiliary capacitor (not shown) provided in parallel therewith. The liquid crystal capacitor is constituted by, for example, a pixel electrode (not shown), a counter electrode (not shown) facing the pixel electrode, and a liquid crystal layer (not shown) between the pixel electrode and the counter electrode. Yes. The drain electrode of the TFT 101 is connected to the pixel electrode. The TFT 101 switches ON / OFF of voltage application to the pixel electrode.

  The photo sensor 102 is disposed in the vicinity of each intersection of the gate line 106 and the signal line 108. A gate line 106 is connected to one end of the photosensor 102, and a signal line 108 is connected to the other end of the photosensor 102.

  When a voltage corresponding to image information is applied to the gate line 106 and the source line 107 from the control unit 131 (FIG. 1), the TFT 101 is turned on, and an image is applied to the liquid crystal display panel 110 by applying a voltage to the pixel electrode. Is displayed. When a predetermined voltage is applied to the gate line 106, a current having a magnitude corresponding to the intensity of light incident on the photosensor 102 flows from the gate line 106 to the signal line 108 via the photosensor 102. For example, the current value increases as the light intensity increases. By detecting the current value, the intensity of the light received by the photosensor 102 can be detected. Note that a diode is provided between the photosensor 102 and the signal line 108 in order to prevent current from flowing from the signal line 108 to the unselected gate (that is, no voltage is applied). obtain.

  FIG. 3A is a cross-sectional view of the TFT 101 and the photosensor 102. FIG. 3B is a top view of the TFT 101 and the photosensor 102. A base coat layer 112 is formed on one substrate 111 (active matrix substrate) of a pair of substrates included in the liquid crystal display panel 110, and the TFT 101 and the photosensor 102 are formed on the base coat layer 112.

  The TFT 101 includes a source region 171, a drain region 172, a gate electrode 173, a channel region 174, a source electrode 175 connected to the source region 171, a drain electrode 176 connected to the drain region 172, and a gate insulating layer. 177. A gate line 106 (FIG. 2) is connected to the gate electrode 173. A source line 107 is connected to the source electrode 175. The drain electrode 176 is connected to a transparent pixel electrode.

  The photosensor 102 includes a P-type amorphous Si region 181, an N-type amorphous Si region 182, and electrodes 183 and 184. A light shielding layer 190 is provided between the glass substrate and the amorphous Si regions 181 and 182. The bottom area of the light shielding layer 190 is larger than the bottom area of the photosensor region (amorphous Si regions 181 and 182). The electrode 183 is connected to the signal line 108, and the electrode 184 is connected to the gate line 106.

  When a voltage is applied to the gate line 106, a voltage is applied to the gate electrode 173 of the TFT 101, and carriers are formed in the channel region 174. In this state, when a voltage is applied to the source line 107, a current flows from the source line 107 to the drain electrode 176, and a voltage is applied to the pixel electrode. By sequentially selecting a gate line 106 and a source line 107 to which a voltage is applied and applying a voltage having a magnitude corresponding to image information, a desired liquid crystal cell 160 is driven to display an image.

  Further, when a voltage is applied to the gate line 106, a voltage is applied to the electrode 184 of the photosensor 102. When light is irradiated to the photosensor 102 in this state, a current flows from the gate line 106 to the signal line 108 through the photosensor 102.

  The detection unit 132 (FIG. 1) detects the intensity of light applied to each of the photosensors 102 connected to the gate line 106 to which a voltage is applied, from the value of the current flowing through each signal line 108. The control unit 131 (FIG. 1) sequentially applies a voltage to each gate line 106 to sequentially switch between the on state and the off state of each pixel unit 150. At the same time, the detection unit 132 (FIG. 1) The value of the current flowing through 108 is sequentially detected. When comparing a case where a pen or a finger is brought into contact with the display surface with a case where no contact is made, the intensity of light received by the photosensor 102 immediately below the contact position changes. It is possible to detect the coordinates of the contact position from the change in intensity.

  The P-type amorphous Si region 181 and the N-type amorphous Si region 182 of the photosensor 102 of this embodiment are all amorphous Si and do not have crystal grain boundaries. Thereby, the variation in the characteristic of a photosensor can be made small. Further, since the source region 171, the drain region 172, and the channel region 174 of the TFT 101 are formed of poly-Si having high electron mobility, good TFT characteristics can be obtained.

  Next, a method for manufacturing the liquid crystal display device 100 will be described. 4A to 4E are views showing a method for manufacturing the liquid crystal display device 100. FIG. In order to clarify the features of the present invention, the manufacturing method of the TFT 101 and the photosensor 102 and the vicinity thereof will be described. In this example, the photosensor 102 is a photodiode.

  Referring to FIG. 4A, molybdenum or the like is deposited on one surface of glass substrate 111 using a sputtering method or the like, and patterned to form light shielding layer 190. The thickness of the light shielding layer 190 is, for example, about 100 nm.

  Thereafter, a base coat layer 112 of silicon oxide and an amorphous Si layer 201 are formed by plasma CVD. The thickness of the base coat layer 112 is about 300 nm, for example, and the thickness of the amorphous Si layer 201 is about 50 nm, for example.

  Next, referring to FIG. 4B, the amorphous Si layer 201 is crystallized by irradiating excimer laser light from the back side of the glass substrate 111. That is, excimer laser light is irradiated to the amorphous Si layer 201 through the glass substrate 111 from the side opposite to the side on which the amorphous Si layer 201 is provided.

  FIG. 5 is a top view showing the crystallization process of the amorphous Si layer 201. In the region where the excimer laser beam is not shielded by the light shielding layer 190 in the amorphous Si layer 201 (the region without the light shielding layer), the amorphous Si is crystallized to form a poly Si region 202. The poly-Si region 202 includes a plurality of poly-Si crystal grains 210, and a boundary between crystal grains becomes a crystal grain boundary 211.

  In the region where the laser light is shielded by the light shielding layer 190 (the region with the light shielding layer), the excimer laser light is shielded and is not irradiated to the amorphous Si, and therefore remains amorphous Si.

  Note that, at the interface between the region with the light shielding layer and the region without the light shielding layer (the position corresponding to the end of the light shielding layer 190), the poly-Si crystal grains grown in the region without the light shielding layer shift to the region with the light shielding layer. For this reason, poly-Si exists in a region having a length (about 2 μm) approximately the same as the size of the poly-Si crystal grains from the interface in the region having the light-shielding layer.

  Next, referring to FIG. 4C, the amorphous Si layer 201 and the poly-Si region 202 are patterned to separate them. The region of the poly Si region 202 becomes a TFT region, and the region of the amorphous Si layer 201 becomes a photodiode region.

  Here, with reference to FIG. 6A, the relationship between the size of the photodiode region and the light shielding layer when the photodiode 102 is shielded from the light of the light source 120 (FIG. 1) will be described.

When the refractive index of the silicon oxide base coat layer 112 is n, the thickness is d, the critical angle is θ, the incident angle of light is θ _0, and the end of the photodiode region is x smaller than the end of the light shielding layer,
n × sin θ = 1 × sin θ ₀
n × sin θ = 1 × sin 90 °
sin θ = 1 / n
x = d × tan θ
Therefore, when n = 1.46 and d = 0.3 μm, x should be about 0.28 μm or more.

  In the present embodiment, considering the shift of the poly-Si crystal grains to the region having the light-shielding layer (FIG. 5), the length (about about the same as the size of the poly-Si crystal grains from the interface in the region having the light-shielding layer. The region of 2 μm) is removed, and the photodiode region is entirely made of amorphous Si. For this reason, the value of x is set so that x> crystal grain size (about 2 μm).

  Further, as shown in FIG. 6B, when considering that the excimer laser light is incident on the glass substrate 111 from an oblique direction, the end portion of the photodiode region 201 is made smaller by y than the end portion of the light shielding layer 190 (y> x + (grain size)).

  As described above, the end portion of the light shielding layer 190 is located at a position extending a predetermined length from the end portion of the photosensor region, and the predetermined length is longer than the length of the polysilicon crystal grains. For example, the end portion of the light shielding layer is positioned so as to extend by 2 μm or more from the end portion of the photosensor. Thereby, even if the poly-Si crystal grains formed at a position corresponding to the end of the light shielding layer 190 are shifted to the photo sensor region side, the photo sensor region can be kept as amorphous silicon.

  After patterning the amorphous Si layer 201 and the poly-Si region 202, a silicon oxide gate insulating layer 177 is formed using a CVD method or the like, as shown in FIG. 4D. The thickness of the gate insulating layer 177 is, for example, about 100 nm.

  After forming the gate insulating layer 177, patterning is performed by forming the gate electrode 173 by using a sputtering method or the like. The material of the gate electrode 173 is, for example, tantalum or tungsten.

  After the formation of the gate electrode 173, ion implantation, activation annealing, and the like are performed, and the source region 171, the drain region 172, the channel region 174 of the TFT 101 (FIG. 3A), the P-type amorphous Si region 181 of the photosensor 102, the N-type amorphous Si region 182 is formed.

  Next, referring to FIG. 4E, a first interlayer insulating layer 204 is formed of silicon oxide or the like. The first interlayer insulating layer 204 is patterned to form contact holes, and aluminum or the like is deposited in the contact holes to form electrodes 175, 176, 183, and 184.

  Next, the second interlayer insulating layer 205 is formed of silicon oxide or an organic insulating material. The second interlayer insulating layer 205 is patterned to form a contact hole, and ITO (indium tin oxide) or the like is deposited on the contact hole and its peripheral region to form the pixel electrode 206.

  The P-type amorphous Si region 181 and the N-type amorphous Si region 182 of the photodiode 102 are all amorphous Si and do not have crystal grain boundaries. Thereby, the variation in the characteristic of a photodiode can be suppressed.

  Further, since the source region 171, the drain region 172, and the channel region 174 of the TFT 101 are formed of poly-Si having high electron mobility, TFT characteristics can be improved.

  In the case where the drive circuit of the liquid crystal display panel 110 is also formed on the glass substrate 111, a drive circuit including the same poly-Si TFT as the TFT 101 may be configured. The TFT of the driver circuit can be manufactured in the same manufacturing process as the TFT 101.

  In the above description, the liquid crystal display device is exemplified as the display device according to the embodiment of the present invention. However, the present invention is not limited to the liquid crystal display device, and may be applied to, for example, an organic EL (Electro Luminescence) display device. The Hereinafter, embodiments of the organic EL display device of the present invention will be described.

(Embodiment 2)
FIG. 7 is a diagram showing an organic EL display device 300 according to the second embodiment of the present invention. The organic EL display device 300 includes a display area 301, and displays an image by a plurality of pixel units 350 arranged in the display area 301.

  The organic EL display device 300 includes a plurality of scanning lines 306, a plurality of data lines 307, and a plurality of power supply lines 308. Scanning lines 306, data lines 307, and power supply lines 308 are provided on a substrate (not shown) in a grid pattern. Data lines 307 and power supply lines 308 are alternately provided in parallel to each other. The scanning lines 306 are arranged in a direction that intersects the data lines 307 and the power supply lines 308. A pixel portion 350 is disposed at each intersection of the scanning line 306 and the data line 307.

  Further, the organic EL display device 300 applies a power supply voltage Vp to the scanning line driving circuit 302 that outputs a scanning signal to the scanning line 306, a data line driving circuit 303 that outputs a data signal to the data line 307, and the power supply line 308. And a Vp power source 304.

  Next, the pixel unit 350 will be described with reference to FIG. FIG. 8 is a diagram showing the pixel portion 350. The pixel unit 350 includes a first TFT 311, a second TFT 312, an organic light emitting diode (OLED) 313, and a capacitor 314.

  The gate electrode of the first TFT 311 is connected to the scanning line 306, the source electrode is connected to the data line 307, and the drain electrode is connected to the gate electrode of the second TFT 312. The source electrode of the second TFT 312 is connected to the power supply line 308, and the drain electrode is connected to the organic light emitting diode 313. The capacitor 314 is connected to the gate electrode and the source electrode of the second TFT 312. The first TFT 311 switches between the ON state and the OFF state of the second TFT 312, and the second TFT 312 changes the voltage supplied to the organic light emitting diode 313 in accordance with the switching between the ON state and the OFF state.

  When the scanning signal is output to the scanning line 306, the data signal is supplied from the data line 307 to the gate electrode of the second TFT 312 via the first TFT 311. Accordingly, the power supply voltage Vp is supplied from the power supply line 308 to the organic light emitting diode 313 via the second TFT 312, and the organic light emitting diode 313 emits light to display an image.

  Here, when the ON current varies among the plurality of second TFTs 312 included in the organic EL display device 300, the luminance of the organic light emitting diode 313 varies, which is visually recognized as unevenness. For this reason, it is important to suppress variations in the ON current of the second TFT 312. In the organic EL display device 300 of the present embodiment, by forming the second TFT 312 with amorphous Si, it is possible to suppress variations in the ON current of the second TFT 312 and to suppress unevenness.

  FIG. 9A is a cross-sectional view of the pixel portion 350, and FIG. 9B is a top view of the pixel portion 350. Each component of the pixel portion 350 is formed on the substrate 111. The semiconductor layer forming the first TFT 311 is made of poly-Si. On the other hand, the semiconductor layer forming the second TFT 312 is formed of amorphous Si, and the light shielding layer 190 is disposed below the semiconductor layer. The bottom area of the light shielding layer 190 is larger than the bottom area of the amorphous Si region of the second TFT 312.

  The first TFT 311 includes a source region 171, a drain region 172, a gate electrode 173, a channel region 174, a source electrode 175 connected to the source region 171, and a drain electrode 176 connected to the drain region 172. The gate electrode 173 is connected to the scanning line 306, and the source electrode 175 is connected to the data line 307.

  The second TFT 312 includes a source region 191, a drain region 192, a gate electrode 193, a channel region 194, a source electrode 195 connected to the source region 191, and a drain electrode 196 connected to the drain region 192.

  The organic light emitting diode 313 includes a pixel electrode 361, an edge cover 362, a hole injection layer 363, a hole transport layer 364, a light emitting layer 365, an electron transport layer 366, an electron injection layer 367, and a cathode 368. It has. The drain electrode 196 of the second TFT 312 is connected to the pixel electrode 361.

  The source region 191, drain region 192, and channel region 194 of the second TFT 312 are all amorphous Si and have no crystal grain boundaries. Thereby, the variation in the characteristics of the second TFT 312 can be reduced. In addition, since the source region 171, the drain region 172, and the channel region 174 of the first TFT 311 are formed of poly-Si having high electron mobility, good TFT characteristics can be obtained.

  Next, a method for manufacturing the organic EL display device 300 will be described. 10A to 10E are diagrams illustrating a method for manufacturing the organic EL display device 300. In order to clarify the characteristics of the present invention, the description will focus on the manufacturing method of the first TFT 311 and the second TFT 312 and the vicinity thereof. In this example, the second TFT 312 is a Pch TFT.

  Referring to FIG. 10A, molybdenum or the like is deposited on one surface of glass substrate 111 using a sputtering method or the like, and patterned to form light shielding layer 190. The thickness of the light shielding layer 190 is, for example, about 100 nm.

  Thereafter, a base coat layer 112 of silicon oxide and an amorphous Si layer 201 are formed by plasma CVD. The thickness of the base coat layer 112 is about 300 nm, for example, and the thickness of the amorphous Si layer 201 is about 50 nm, for example.

  Next, referring to FIG. 10B, the amorphous Si layer 201 is crystallized by irradiating excimer laser light from the back side of the glass substrate 111. That is, excimer laser light is irradiated to the amorphous Si layer 201 through the glass substrate 111 from the side opposite to the side on which the amorphous Si layer 201 is provided.

  As described with reference to FIG. 5, in the region of the amorphous Si layer 201 where the excimer laser light is not shielded by the light shielding layer 190 (the region without the light shielding layer), the amorphous Si is crystallized to form the poly Si region 202. The The poly-Si region 202 includes a plurality of poly-Si crystal grains 210, and a boundary between crystal grains becomes a crystal grain boundary 211.

  In the region where the laser light is shielded by the light shielding layer 190 (the region with the light shielding layer), the excimer laser light is shielded and is not irradiated to the amorphous Si, and therefore remains amorphous Si.

  Note that, at the interface between the region with the light shielding layer and the region without the light shielding layer (the position corresponding to the end of the light shielding layer 190), the poly-Si crystal grains grown in the region without the light shielding layer shift to the region with the light shielding layer. For this reason, poly-Si exists in a region having a length (about 2 μm) approximately the same as the size of the poly-Si crystal grains from the interface in the region having the light shielding layer.

  Next, referring to FIG. 10C, the amorphous Si layer 201 and the poly-Si region 202 are patterned to separate them. The region of the poly-Si region 202 becomes the first TFT 311 region, and the region of the amorphous Si layer 201 becomes the second TFT 312 region.

  As described with reference to FIGS. 6A and 6B, the end portion of the light shielding layer 190 is positioned so as to extend by 2 μm or more from the end portion of the second TFT 312. Thereby, even if the poly-Si crystal grains formed at the position corresponding to the end portion of the light shielding layer 190 are shifted to the second TFT 312 region side, the second TFT 312 region can be maintained as amorphous silicon.

  After patterning the amorphous Si layer 201 and the poly-Si region 202, a silicon oxide gate insulating layer 177 is formed using a CVD method or the like, as shown in FIG. 10D. The thickness of the gate insulating layer 177 is, for example, about 100 nm.

  After the gate insulating layer 177 is formed, gate electrodes 173 and 193 are formed using a sputtering method or the like to perform patterning. The material of the gate electrodes 173 and 193 is, for example, tantalum or tungsten.

  After forming the gate electrode 173, ion implantation, activation annealing, and the like are performed, and the source region 171, the drain region 172, the channel region 174, and the source region 191 and the drain region of the second TFT 312 (FIG. 9A) of the first TFT 311 (FIG. 9A). 192 and a channel region 194 are formed.

  Next, the gate insulating layer 177 is patterned to form a contact hole, and aluminum or the like is deposited in the contact hole to form the drain electrode 176.

  Next, referring to FIG. 10E, a first interlayer insulating layer 204 is formed of silicon oxide or the like. The first interlayer insulating layer 204 is patterned to form contact holes, and aluminum or the like is deposited in the contact holes to form source electrodes 175 and 195 and a drain electrode 196.

  Next, the second interlayer insulating layer 205 is formed of silicon oxide or an organic insulating material. The second interlayer insulating layer 205 is patterned to form a contact hole, and ITO (indium tin oxide) or the like is deposited on the contact hole and its peripheral region to form a pixel electrode 361.

  Next, referring to FIG. 10F, an edge cover 362 is formed on the pattern edge of the pixel electrode 361. The edge cover 362 forms a pattern of a photoresist including at least one of a phenol resin, a polyimide resin, a novolac resin, and an acrylic resin by a known photo process.

  Further, as the hole injection layer 363 and hole transport layer 364, NPB (N, N-di (naphthalene-1-yl) -N, N-diphenyl-benzidine) is 30 nm thick, the light emitting layer 365 is 30 nm, and the electron transport layer is As the 366-cum-electron injection layer 367, Alq3 (aluminum quinolinol complex (aluminato-tris-8-hydroxyquinolate)) and a magnesium-silver alloy as the translucent cathode 368 are continuously formed by a vapor deposition method with a film thickness of 5 nm. The light emitting layer 365 is formed by a coating method using vapor deposition masks corresponding to red (R), green (G), and blue (B).

  Then, it seals with sealing glass using an epoxy resin, and the active matrix organic electroluminescent display apparatus 300 is completed.

  The source region 191, drain region 192, and channel region 194 of the second TFT 312 are all amorphous Si and have no crystal grain boundaries. Thereby, the variation in the characteristics of the second TFT 312 can be reduced. In addition, since the source region 171, the drain region 172, and the channel region 174 of the first TFT 311 are formed of poly-Si having high electron mobility, TFT characteristics can be improved.

  When the drive circuit of the organic EL display device 300 is also formed on the glass substrate 111, a drive circuit including the same poly-Si TFT as the first TFT 311 may be configured. The TFT of the drive circuit can be manufactured in the same manufacturing process as the first TFT 311.

  The present invention is particularly useful in the technical field of display devices and touch panels including TFTs.

It is a figure which shows the liquid crystal display device by embodiment of this invention. It is a figure which shows the liquid crystal display panel by embodiment of this invention. It is a figure which shows TFT and photosensor by embodiment of this invention. It is a figure which shows TFT and photosensor by embodiment of this invention. It is a figure which shows the manufacturing method of the liquid crystal display device by embodiment of this invention. It is a figure which shows the manufacturing method of the liquid crystal display device by embodiment of this invention. It is a figure which shows the manufacturing method of the liquid crystal display device by embodiment of this invention. It is a figure which shows the manufacturing method of the liquid crystal display device by embodiment of this invention. It is a figure which shows the manufacturing method of the liquid crystal display device by embodiment of this invention. It is a figure which shows the crystallization process of the amorphous Si layer by embodiment of this invention. It is a figure which shows the relationship of the size of the photodiode area | region and light shielding layer by embodiment of this invention. It is a figure which shows the relationship of the size of the photodiode area | region and light shielding layer by embodiment of this invention. It is a figure which shows the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the pixel part of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the pixel part of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the pixel part of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows the manufacturing method of the organic electroluminescent display apparatus by embodiment of this invention. It is a figure which shows a touchscreen integrated display device.

Explanation of symbols

100 Liquid crystal display device 110 Liquid crystal display panel 101 TFT
102 Photosensor 111 Substrate 112 Basecoat layer 120 Light source 131 Control unit 132 Detection unit 171 Source region 172 Drain region 173 Gate electrode 174 Channel region 177 Gate insulating layer 181 P-type amorphous Si region 182 N-type amorphous Si region 190 Light-shielding layer 206 Pixel electrode

Claims (10)

A display device including a plurality of pixel portions,
Each of the plurality of pixel portions is
A pixel electrode;
A transistor for switching ON / OFF of voltage application to the pixel electrode;
A photosensor that receives light incident on the pixel portion;
The transistor has a source region, a drain region and a channel region formed of polysilicon,
The photosensor has a P-type amorphous silicon region and an N-type amorphous silicon region. The display device further includes a light source that emits light,
Each of the plurality of pixel portions is
A light shielding layer disposed between the photosensor and the light source;
The display device according to claim 1, wherein a bottom area of the light shielding layer is larger than a bottom area of the photosensor. The end of the light shielding layer is at a position extending a predetermined length from the end of the photosensor,
The display device according to claim 2, wherein the predetermined length is longer than a length of polysilicon crystal grains.   3. The display device according to claim 2, wherein an end portion of the light shielding layer is located at a position extending from the end portion of the photosensor by 2 μm or more. Forming a light shielding layer at a position on one side of the glass substrate;
Forming an amorphous silicon layer at a position opposite to the glass substrate of the light shielding layer;
Irradiating the amorphous silicon layer with light through the glass substrate to crystallize a part of the amorphous silicon layer;
Separating the polysilicon region formed by crystallization from the amorphous silicon region;
Forming a gate electrode of a transistor at a position on the opposite side of the polysilicon region from the glass substrate;
Performing ion implantation into the polysilicon region to form a source region and a drain region of the transistor;
Forming a photosensor including a P-type amorphous silicon region and an N-type amorphous silicon region by performing ion implantation on the amorphous silicon region. A display device including a plurality of pixel portions,
Each of the plurality of pixel units includes first and second transistors and an organic light emitting diode,
The first transistor switches between the ON state and the OFF state of the second transistor,
The second transistor changes a voltage supplied to the organic light emitting diode according to switching between an ON state and an OFF state,
The first transistor has a source region, a drain region and a channel region formed of polysilicon,
The second transistor has a source region, a drain region, and a channel region formed of amorphous silicon. The display device further includes a substrate on which the first and second transistors are formed,
Each of the plurality of pixel portions further includes a light shielding layer disposed between the second transistor and the substrate,
The display device according to claim 6, wherein a bottom area of the light shielding layer is larger than a bottom area of the second transistor. The end of the light shielding layer is at a position extending a predetermined length from the end of the second transistor,
The display device according to claim 7, wherein the predetermined length is longer than a length of polysilicon crystal grains.   8. The display device according to claim 7, wherein an end portion of the light shielding layer is located at a position extending by 2 μm or more from an end portion of the second transistor. Forming a light shielding layer at a position on one side of the glass substrate;
Forming an amorphous silicon layer at a position opposite to the glass substrate of the light shielding layer;
Irradiating the amorphous silicon layer with light through the glass substrate to crystallize a part of the amorphous silicon layer;
Separating the polysilicon region formed by crystallization from the amorphous silicon region;
Forming a gate electrode of a first transistor at a position on the opposite side of the polysilicon region from the glass substrate;
Forming a gate electrode of a second transistor at a position opposite to the glass substrate in the amorphous silicon region;
Forming a source region and a drain region of each of the first and second transistors by implanting ions into the polysilicon region and the amorphous silicon region.

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