TWI430434B - Resistive memory device and its manufacturing method - Google Patents

Description

Resistive memory and manufacturing method thereof

The present invention relates to a memory and a method of fabricating the same, and more particularly to a resistive memory and a method of fabricating the same.

Memory has been widely used in various electronic products, and has become one of the indispensable components in electronic products. Therefore, research and development related to memory have also received attention from the industry.

A conventional resistive memory is generally shown in FIG. 1a, and includes a first electrode 91, a second electrode 92, and a resistance switching reaction layer 93. The resistance switching reaction layer 93 is coupled to the first Between the electrode 91 and the second electrode 92; the resistance switching reaction layer 93 is usually made of a metal oxide, and contains a reducing species which promotes the reduction reaction and an oxidized species which promotes redox.

Referring to FIG. 1a again, when a voltage is applied to the first electrode 91 and the second electrode 92, the oxidized species and the reduced species in the material of the resistance switching reaction layer 93 cause the redox reaction to proceed. The resistance switching reaction layer 93 forms a filament 94 or after the wire 94 is formed, and then the wire 94 is broken, thereby causing a change in the resistance value of the resistance switching reaction layer 93, and thus can be used as a memory. In addition, after the resistance value is switched, the conventional resistance-type memory device finally returns to the state of returning to the oxide, and can be used for the next time.

As shown in Fig. 1a, the presence of oxygen atoms is required during the oxidation-reduction reaction described above for oxidation of the metal atoms. However, since the oxygen atoms are uniformly distributed in the resistance switching reaction layer 93, the formed wires 94 are randomly extended from the second electrode 92 toward the first electrode 91 during the resistance switching, and The length and path of the extension are not fixed, so the resistance value will be different during the continuous switching of the voltage, and the resistance value after the switching will be different, resulting in the disadvantage of poor stability of the resistance performance.

Furthermore, as shown in FIG. 1b, after the conventional switching memory is used, the conventional oxygen-reduction reaction is performed, and the oxygen atoms 95 generated during the reduction process gradually dissipate. When the oxygen atom 95 which is dissipated in the resistance switching reaction layer 93 is excessive, the resistance state cannot be restored to the oxidation state, and the resistance switching characteristic is lost, so that the resistance memory life and the life of the resistance memory element are not good.

Another conventional resistive memory, as described in the invention patent of the Chinese Patent Publication No. I311811, "Semiconductor Memory Device Containing Variable Resistor Components", includes a first electrode, a second electrode, and a variable resistor. And a reaction blocking film. The variable resistance system is disposed between the first electrode and the second electrode to jointly form a variable resistance memory; the reaction preventing film is coated on the entire surface of the variable resistance memory. The reaction prevents the material of the membrane from blocking the penetration of the reducing species and the oxidizing species. In order to prevent the oxygen atoms from escaping, and to avoid fluctuations in the resistance value, it is possible to obtain a semiconductor memory device which is excellent in reproducibility and stably produces a low resistance value deviation and has good controllability.

However, the resistive memory of the No. I311811 can prevent the oxygen atoms from escaping through the reaction through the reaction. However, the reaction blocking film arrangement will cause the resistive memory process to be additionally semiconductor The process, for example, the reaction preventing film is formed by sputtering, so the manufacturing method increases the complexity of the process and the manufacturing cost; in addition, the disadvantage that the reaction prevents the film from being unstable to the previously formed wire path cannot be improved. It still has the disadvantage of poor resistance stability.

For the above reasons, it is necessary to further improve the above-described conventional resistive memory and a method of fabricating the same.

It is an object of the present invention to improve the above disadvantages to provide a resistive memory for the purpose of avoiding the escape of oxygen atoms.

A second object of the present invention is to provide a resistive memory for fixing the length of oxidation of the wire.

Still another object of the present invention is to provide a method of fabricating a resistive memory to fabricate the aforementioned resistive memory.

The resistive memory according to the present invention comprises: a first electrode; a sulphate layer disposed on a surface of the first electrode, wherein the anodic layer is made of an oxide material containing an oxygen absorbing atom, wherein The oxygen-absorbing atom is a nitrogen, fluorine or chlorine atom; a dielectric layer is made of an oxide material and is disposed on the surface of the oxygen-absorbing layer such that the oxygen-containing layer is located at the first electrode and Between the electrical layers, and the attraction of the dielectric layer to oxygen atoms is less than the attraction of the oxygen layer to the oxygen atoms; a second electrode is disposed on the surface of the dielectric layer to make the dielectric layer Located between the second electrode and the anodic layer. Thereby, the resistance value of the resistive memory is stabilized.

The method for fabricating a resistive memory according to the present invention comprises: a step of fabricating an oxo layer, depositing an oxide on a surface of a first electrode, and Doping an oxygen-absorbing atom into the oxide material to form a first anodic oxygen layer, wherein the oxygen-absorbing atom is a nitrogen, fluorine or chlorine atom; a dielectric layer forming step, the oxide is disposed on the oxide layer The surface of the oxo layer forms a dielectric layer, and the anodic layer is interposed between the dielectric layer and the first electrode, wherein the dielectric layer has a lower attraction to oxygen atoms than the anodic layer The attraction of the oxygen atoms; and an electrode fabrication step of disposing a second electrode on the surface of the dielectric layer such that the dielectric layer is interposed between the anodic layer and the second electrode.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Referring to FIGS. 2 and 3, the resistive memory system of the present invention comprises a first electrode 1, at least one sulphide layer 2, a dielectric layer 3, and a second electrode 4.

Referring to FIG. 2, the first electrode 1 and the second electrode 4 of the present embodiment are preferably made of a material having good conductivity, and may be selected from tungsten, aluminum, titanium, copper, nickel, silver, gold. Made of platinum, titanium nitride or other materials.

Referring to FIG. 2, the first oxic layer 2 of the present embodiment is formed on the surface of the first electrode 1. The first sulphate layer 2 is made of an oxide material containing an oxygen absorbing atom, such that the first oxo layer 2 has an attractive force for oxygen atoms greater than the dielectric layer 3 to attract oxygen atoms, and The oxygen atom content of the first oxo layer 2 is made larger than the oxygen atom content of the dielectric layer 3. More specifically, the first oxic layer 2 of the present embodiment is made of an oxide material containing an oxygen-absorbing atom, such as a nitrogen, fluorine or chlorine atom. An atom that is highly attractive to oxygen atoms. For example, if an atom such as a nitrogen atom or a fluorine atom is doped into an oxide such as aluminum oxide, titanium oxide, nickel oxide, zinc oxide, copper oxide, cerium oxide or cerium oxide, the first oxidized layer 2 can be used. Material. For example, the first anodic oxide layer 2 of the present embodiment is selected to be made of an oxide (nitrogen oxide-containing) material containing a nitrogen atom.

Referring to FIG. 2, the dielectric layer 3 of the present embodiment is disposed on the surface of the first anodic oxide layer 2, such that the first anodic oxide layer 2 is located on the first electrode 1 and the dielectric layer 3. The dielectric layer 3 is made of an oxide material, preferably made of a metal oxide such as aluminum oxide, titanium oxide, nickel oxide, zinc oxide, copper oxide or hafnium oxide (HfO ₂ ). Or made of yttrium oxide (SiGeO). When the resistive memory is operated, the dielectric layer 3 is subjected to a redox reaction to cause a change in the resistance state. Thus, the dielectric layer 3 and the first oxo layer 2 will collectively form a two-layer structure of "oxide/nitrogen oxide" to attract oxygen atoms by the presence of the nitrogen atoms, thereby confining oxygen atoms. The first culvert layer 2 is.

Referring to FIG. 2, the second electrode 4 of the present embodiment is formed on the surface of the dielectric layer 3 such that the dielectric layer 3 is located between the first anodic oxide layer 2 and the second electrode 4.

Of course, as shown in FIG. 3, after the second Mn layer 2' is disposed on the surface of the dielectric layer 3, the second electrode 4 is disposed on the surface of the second Mn layer 2'. The dielectric layer 3 is interposed between the first anodic layer 2 and the second anodic layer 2'. The material and characteristics of the second Mn-containing layer 2' and the first Mn-containing layer 2 are the same, and both have good attraction to oxygen atoms, and will not be described herein.

Taking the 4a and 4b as an example, when the resistive memory of the embodiment is used, a negative voltage and a positive voltage are applied to the first electrode 1 (-) and the second electrode 4 (+), respectively. The metal oxide in the dielectric layer 3 will respectively generate metal atoms and oxygen atoms due to the redox reaction, and since the first oxo layer 2 has a stronger attraction and capture ability to oxygen atoms than the dielectric layer 3, Therefore, the dissipated oxygen atoms will be attracted into the first oxo layer 2, so that the oxygen atom content in the first anoxia layer 2 is higher than that of the dielectric layer 3; The formation or fracture process of the wire A requires the presence of an oxygen atom, and the first oxo layer 2 having a high oxygen atom content will facilitate the redox reaction, so that the wire A will be extended from the second electrode 4 to the The first culvert layer 2. Therefore, the formation length and path of the wire A can be stabilized, and the electrical resistance of the reaction is improved, and the stability of the switching resistance value and the memory state are improved.

Meanwhile, referring to FIG. 4b, since the first oxo layer 2 contains an oxygen-absorbing atom (nitrogen atom C), the lone pair of electrons of the nitrogen atom C will combine with the dissipated oxygen atom B to form a common Coordinating the covalent bond, therefore, the first oxo layer 2 will capture the oxygen atom B, and can confine the escape of oxygen in the vicinity of the electron transport path (wire A), thereby making the resistive memory reliable Degree can be effectively improved.

Wherein, the thickness of the Mn layer 2 is preferably 3~10 nm, and the thickness is the distance between the formation and the break of the wire. If the thickness of the Mn layer 2 is higher than 10 nm, the Mn layer 2 is in the resistive memory. If the proportion of the wire in the body is too high, the position of the wire in the oxidized layer 2 may have a large change, and the length of the wire is unstable, so that the effect of stabilizing the resistance value is not good; If the thickness of layer 2 is less than 3 nm, the sulphide layer 2 is too thin for oxygen. Poor limitations will also affect the performance of the resistive memory. For example, the thickness of the first electrode 1 of the present embodiment is 100 nm, the thickness of the second electrode 4 is 100 m, the thickness of the dielectric layer 3 is 25 nm, and the thickness of the Mn-containing layer 2 is 50 nm.

As described above, the resistive memory of the present invention utilizes the oxo layers 2, 2' to trap oxygen atoms to prevent oxygen atoms from escaping, while stabilizing the formation length and path of the wire A, thereby stabilizing the switching resistance value.

The method for fabricating the resistive memory of the present invention comprises: a sulphur layer manufacturing step, a dielectric layer forming step, and an electrode forming step.

Referring to FIG. 2, the oxo layer is formed by depositing the foregoing oxide material on the surface of the first electrode 1 and doping the oxygen-absorbing atoms into the oxide material to form the first layer. A culvert layer 2. In more detail, the first electrode 1 is selected as titanium nitride. In this embodiment, an oxide material may be deposited on the first electrode by physical vapor deposition (for example, sputtering) or chemical vapor deposition. The surface of the oxygen absorbing atom may be selected from the gas material during the deposition process of the oxide material or the gas which is introduced into the oxygen atom during the thermal annealing process, or the surface of the plasma is treated to make the suction An oxygen atom is blended in the oxide material to form the first oxo layer 2. For example, in this embodiment, nitrogen (oxygen atom) is introduced into the process of depositing cerium oxide by sputtering, so that the first oxidic layer 2 formed by deposition contains a component of nitrogen atoms for transmission. This nitrogen atom increases the attraction to oxygen atoms. The sputtering operation conditions are as follows: the target is cerium oxide (SiGeO), argon gas is 30 sccm and ammonia gas is 10 sccm to 6 mtorr, the substrate pressure is 9×10 ^-6 torr, and the deposition thickness is 5 nm.

Referring to FIG. 2, the dielectric layer is formed by disposing an oxide material on the surface of the first oxo layer 2 to form the dielectric layer 3, so that the first anodic layer 2 is interposed. The electrical layer 3 is between the first electrode 1. More specifically, the oxide material in this step may be selected from the group consisting of aluminum oxide, titanium dioxide, nickel oxide, zinc oxide, copper oxide, cerium oxide or cerium oxide, or may be selected from the physical gas phase. The dielectric layer 3 is deposited on the surface of the first anodic oxide layer 2 by deposition or chemical vapor deposition. For example, in the present embodiment, the dielectric layer 3 is formed by sputtering. The sputtering operation conditions are as follows: the target is cerium oxide (SiGeO), argon gas is 30 sccm and oxygen is 10 sccm to 6 mtorr, the substrate pressure is 9×10 ^-6 torr, and the deposition thickness is 25 nm.

Referring to FIG. 2 again, the electrode fabrication step is performed by disposing the second electrode 4 on the surface of the dielectric layer 3 such that the dielectric layer 3 is interposed between the first anodic oxide layer 2 and the second electrode. Between 4. More specifically, a metal material is deposited on the surface of the dielectric layer 3 by chemical vapor deposition or physical vapor deposition to form the second electrode 4. In this embodiment, a platinum film is grown as a second electrode 4 by a sputtering system.

In addition, if the resistive memory as shown in FIG. 3 is to be formed, it is only necessary to deposit the oxide material in the manner described in the anodic layer fabrication step after the dielectric layer fabrication step is completed. a surface of the dielectric layer 3, and doping oxygen-absorbing atoms into the oxide material to form another second anodic oxide layer 2', so that the dielectric layer is sandwiched between the two Mn-oxide layers 2, 2 'between. Finally, the electrode fabrication step is performed, and the second electrode is disposed on the surface of the second anodic layer 2 to complete the fabrication of the resistive memory as shown in FIG.

In order to verify that the resistive memory of the present invention does have the aforementioned effects, the following electrical measurement analysis is performed:

The following analysis is performed for a conventional resistive memory (hereinafter referred to as a control group) and a resistive memory of the present invention (hereinafter referred to as an experimental group). The first electrode 1 of the control group and the experimental group are made of titanium nitride, the second electrode 4 is made of platinum, and the dielectric layer 3 is made of bismuth oxide (SiGeO). As shown in Fig. 2, an oxo layer 2 made of nitrided tantalum oxide (SiGeO) is additionally provided.

Please refer to the figure 5a, which is the switching voltage distribution map of the control group. It can be clearly seen from the results that since the control group is not fixed after each switching of the voltage, the electron transport path formed every time is not fixed. As a result of the wide switching voltage distribution as shown in Fig. 5a (the switching voltage is from 0.8V to 1.5V or more), the switching voltage is not stable.

Please refer to FIG. 5b, which is a switching voltage distribution diagram of the experimental group. It can be clearly seen from the results that since the resistive memory of the present invention is additionally provided with the sulphide layer 2, the electron transport path can be made as described above. It is relatively stable, and it can be known from the measurement results that the switching voltage is quite concentrated, and there is no disadvantage that the switching voltage of the control group is unstable. It can be verified that the resistive memory of the present invention does have a fixed electron transmission path and a stable switching voltage. efficacy.

Please refer to Figure 6a, which is the resistance stability of the control group. As the control group has the disadvantages of oxygen atom escaping and unstable electron transport path, the results show that it does cause resistance to the formation. The state is unstable and there is a cracking condition, so the durability and stability are not good.

Referring to FIG. 6b, which is the resistance stability of the experimental group of the present invention, it is apparent from the results that the resistive memory of the present invention can avoid the escape of oxygen atoms and stabilize the electron transport path. Therefore analyzing the knot It can be seen that the resistance state of the experimental group is stable and no cracking occurs. It can be verified that the resistive memory of the present invention does have the effect of stabilizing resistance.

Therefore, the resistive memory of the present invention can block the length and path of the wire while capturing oxygen atoms while passing through the sulphate layer 2, thereby stabilizing the switching voltage and the resistance value, and improving the durability and stability.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

[this invention]

1‧‧‧first electrode

2‧‧‧First oxo layer

2'‧‧‧Second oxo layer

3‧‧‧ dielectric layer

4‧‧‧second electrode

A‧‧‧Wire

B‧‧‧Oxygen atom

C‧‧‧ nitrogen atom

[Prior technology]

91‧‧‧First electrode

92‧‧‧second electrode

93‧‧‧Resistance switching reaction layer

94‧‧‧Wire

95‧‧‧Oxygen atom

Figure 1a: A cross-sectional view of a conventional resistive memory structure.

Figure 1b: A partial enlarged view of a conventional resistive memory.

Fig. 2 is a cross-sectional view showing the structure of the resistive memory of the present invention.

Figure 3 is a cross-sectional view showing the structure of a resistive memory according to another embodiment of the present invention.

Figure 4a is a schematic diagram of the operation of the resistive memory of the present invention.

Figure 4b is a partial enlarged view of the resistive memory of the present invention.

Figure 5a: Switching voltage distribution of the control group.

Figure 5b: Switching voltage distribution of the experimental group.

Figure 6a: Figure of the resistance stability test results of the control group.

Figure 6b: Diagram of the results of the resistance stability test of the experimental group.

1. . . First electrode

2. . . First oxo layer

3. . . Dielectric layer

4. . . Second electrode

Claims (9)

A resistive memory comprising: a first electrode; a sulphate layer disposed on a surface of the first electrode, the anodic layer being made of an oxide material containing an oxygen absorbing atom, wherein the oxygen absorbing atom Is a nitrogen, fluorine or chlorine atom; a dielectric layer is made of an oxide material and is disposed on the surface of the oxo layer such that the anodic layer is between the first electrode and the dielectric layer And the attraction of the dielectric layer to the oxygen atom is less than the attraction of the oxygen layer to the oxygen atom; and a second electrode is disposed on the surface of the dielectric layer such that the dielectric layer is located at the first Between the two electrodes and the culvert layer. The resistive memory according to claim 1, wherein the thickness of the anodic layer is 3 to 10 nm. The resistive memory according to claim 1, wherein the oxide containing oxygen-absorbing atoms is aluminum oxide, titanium oxide, nickel oxide, zinc oxide, copper oxide or cerium oxide containing oxygen-absorbing atoms. Or bismuth oxide. A resistive memory comprising: a first electrode; a first anodic layer disposed on a surface of the first electrode, the anodic layer being made of an oxide material containing an oxygen absorbing atom; a dielectric The layer is made of an oxide material and is disposed on the surface of the first ox layer, such that the first anodic layer is located at the first electrode and the dielectric Between the layers; a second sulphide layer disposed on the surface of the dielectric layer such that the dielectric layer is between the first anodic oxylayer and the second sulphide layer, and the second sulphide sulphide layer The material is made of an oxide material containing an oxygen-absorbing atom, and the first anodic oxygen layer and the second anodic oxygen layer are more attractive to oxygen atoms than the oxygen layer of the dielectric layer, wherein the oxygen is absorbed. The atomic system is a nitrogen, fluorine or chlorine atom; and a second electrode is disposed on the surface of the second oxo layer such that the second anodic layer is between the second electrode and the dielectric layer. A method for fabricating a resistive memory, comprising: a step of fabricating an oxo layer, depositing an oxide on a surface of a first electrode, and doping an oxygen-absorbing atom into the oxide material to form a sulphide a layer, wherein the oxygen-absorbing atom is a nitrogen, fluorine or chlorine atom; a dielectric layer forming step of disposing an oxide on a surface of the oxo layer to form a dielectric layer, and the anodic layer is interposed Between the dielectric layer and the first electrode, wherein the dielectric layer has an attraction force to the oxygen atom that is less than the attraction of the oxygen layer to the oxygen atom; and an electrode fabrication step of placing a second electrode on the dielectric layer The surface of the electrical layer is such that the dielectric layer is interposed between the anodic layer and the second electrode. The method for fabricating a resistive memory according to claim 5, wherein after the step of fabricating the dielectric layer, the oxide material is further deposited on the surface of the dielectric layer, and the oxygen-absorbing atoms are doped. After the oxide material is formed to form a second anodic oxide layer, the electrode fabrication step is performed, and the second electrode is disposed on the surface of the second anodic oxide layer. Producer of resistive memory according to item 5 of the patent application scope In the step of fabricating the oxo layer, the oxygen-absorbing atoms are introduced into the oxide material to cause the oxygen-absorbing atoms to be doped into the oxide material to form the first anodic oxide layer. The method for fabricating a resistive memory according to claim 5, wherein in the step of fabricating the oxygen layer, the oxygen-absorbing atom is doped into the oxide material by plasma modification to form the first A culvert layer. The method for fabricating a resistive memory according to claim 5, wherein in the step of fabricating the oxidized layer, after the oxide material is deposited, an annealing process is performed, and the oxygen-absorbing atom is simultaneously introduced. The oxygen absorbing atom is doped into the oxide material to form the first anodic oxide layer.