Resistive random access memory and manufacturing method thereof

Abstract

The present invention provides a resistive random access memory, comprising: a first electrode layer and a second electrode layer, which are arranged opposite to each other; a variable resistance layer, which is located between the first electrode layer and the second electrode layer; an oxygen exchange layer, which is located between the variable resistance layer and the second electrode layer; a vacancy providing layer, which is located around the middle side wall surrounding the oxygen exchange layer; and a vacancy driving electrode layer, which is located on the vacancy providing layer and surrounds the upper side wall of the oxygen exchange layer.

Description

Technical Field

[0001] The embodiments of the present invention relate to a memory and a manufacturing method thereof, and more particularly to a resistive random access memory (RRAM) and a manufacturing method thereof. Background Art

[0002] RRAM has the advantages of fast operation speed and low power consumption, and thus has become a kind of non-volatile memory widely studied in recent years. When performing the set (SET) operation of RRAM, a positive voltage is applied to the resistance random access memory. The oxygen ions in the variable resistance layer will enter the oxygen exchange layer after being attracted by the positive voltage to leave the variable resistance layer. The variable resistance layer will produce oxygen vacancies (oxygen vacancy) to form filaments and present a conductive state. At this time, the variable resistance layer is converted from a high resistance state (High Resistance State, HRS) to a low resistance state (Low Resistance State, LRS). When the RRAM unit 10 performs a reset (RESET) operation, a negative bias is applied to the resistance random access memory, and the oxygen ions in the oxygen exchange layer will return to the variable resistance layer, causing the filaments to break and present a non-conductive state. At this time, the variable resistance layer is converted from LRS to HRS. However, if the oxygen vacancies generated in the variable resistance layer are insufficient, the current of the low resistance state (LRS) will be insufficient. In addition, some of the filaments in the variable resistance layer are likely to be damaged in the subsequent baking process, causing the RRAM to have insufficient current during operation. Although applying a higher operating voltage to the RRAM can drive more oxygen vacancies, it will result in greater power consumption. Summary of the invention

[0003] The present invention is directed to a resistance random access memory and a manufacturing method thereof, which can make the resistance random access memory have sufficient current, avoid using excessive operating voltage, and reduce power consumption.

[0004] According to an embodiment of the present invention, a resistive random access memory includes a first electrode layer and a second electrode layer, which are arranged opposite to each other; a variable resistance layer, located between the first electrode layer and the second electrode layer; an oxygen exchange layer, located between the variable resistance layer and the second electrode layer; a vacancy providing layer, located around a middle side wall surrounding the oxygen exchange layer; and a vacancy driving electrode layer, located on the vacancy providing layer, surrounding an upper side wall of the oxygen exchange layer.

[0005] According to an embodiment of the present invention, a method for manufacturing a resistive random access memory includes forming a variable resistance layer on a first electrode layer; forming a vacancy supply layer on the variable resistance layer; forming a vacancy drive electrode layer on the vacancy supply layer; forming a first opening in the vacancy drive electrode layer; forming a first oxygen barrier layer in the first opening; forming a second opening in the first oxygen barrier layer, the vacancy supply layer, and the vacancy barrier layer; forming an oxygen exchange layer in the second opening; forming a second oxygen barrier layer on the vacancy drive electrode layer and the oxygen exchange layer; and forming a second electrode layer on the second oxygen barrier layer.

[0006] Based on the above, an embodiment of the present invention provides a resistive random access memory and a manufacturing method thereof. By setting a vacancy driving electrode layer and a vacancy providing layer, oxygen vacancies can be increased so that the resistive random access memory has sufficient current, avoids using an excessively large operating voltage, and reduces power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figures 1A to 1G It is a cross-sectional schematic diagram of a manufacturing process of a resistance random access memory according to an embodiment of the present invention. DETAILED DESCRIPTION

[0008] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0009] Please refer to Figure 1G The resistive random access memory (RRAM) cell 10 includes a first electrode 102, a variable resistance layer 104, a second electrode 120, a vacancy blocking layer 106, a vacancy supply layer 108, a vacancy driving electrode layer 110, an oxygen exchange layer 116a, a first oxygen blocking layer 114a and a second oxygen blocking layer 118.

[0010] The first electrode 102 may be connected to a conductive feature below, such as a via plug 100. The via plug 100 may be, for example, any via plug in a dielectric layer 99 of a metal interconnect structure formed on a substrate. The via plug 100 may be, for example, a via plug at the same height as a first via plug in contact with a first metal layer closest to the substrate. The substrate may be a semiconductor substrate or a semiconductor-on-insulator (SOI) substrate. Other components, such as transistors, may be included between the substrate and the first metal layer.

[0011] The first electrode layer 102 and the second electrode 120 are disposed correspondingly. The materials of the first electrode layer 102 and the second electrode 120 may include metal, metal nitride, other materials or a combination thereof. The materials of the first electrode layer 102 and the second electrode 120 are, for example, titanium nitride (TiN), tantalum nitride (TaN), titanium aluminum nitride (TiAlN), titanium tungsten (TiW) alloy, platinum (Pt), iridium (Ir), ruthenium (Ru), titanium (Ti), tungsten (W), tantalum (Ta), aluminum (Al), zirconium (Zr), hafnium (Hf), nickel (Ni), copper (Cu), cobalt (Co), iron (Fe), gadolinium (Gd), manganese (Mo), graphite or a combination of the above materials, and the formation method thereof may be, for example, physical vapor deposition or chemical vapor deposition. The first electrode layer 102 and the second electrode 120 may be a single layer or a multilayer. The thickness of the first electrode layer 102 and the second electrode 120 is not particularly limited, but is generally between 5 nanometers (nm) and 500 nanometers.

[0012] The variable resistance layer 104 is located between the first electrode layer 102 and the second electrode 120. The variable resistance layer 104 may have the following characteristics: when a positive voltage is applied to the resistance random access memory, oxygen ions are attracted by the positive voltage to leave the variable resistance layer 104 and generate oxygen vacancies, forming filaments and presenting a conductive state. At this time, the variable resistance layer 104 is converted from a high resistance state (HRS) to a low resistance state (LRS). When a negative bias is applied to the resistance random access memory, oxygen ions will enter the variable resistance layer 104, causing the filaments to break and present a non-conductive state. At this time, the variable resistance layer 104 is converted from LRS to HRS. Generally speaking, the conversion of the variable resistance layer 104 from HRS to LRS is called a set (hereinafter referred to as SET) operation, and the conversion of the variable resistance layer 104 from LRS to HRS is called a reset (hereinafter referred to as RESET) operation. The material of the variable resistance layer 104 is not particularly limited, as long as it is a material that can change its own resistance by applying a voltage. In the present embodiment, the material of the variable resistance layer 104 includes a metal oxide, such as hafnium oxide (HfO2), tantalum oxide (Ta2O5), titanium oxide (TiO2), magnesium oxide (MgO), nickel oxide (NiO), niobium oxide (Nb2O5), aluminum oxide (Al2O3), vanadium oxide (V2O5), tungsten oxide (WO3), zinc oxide (ZnO) or cobalt oxide (CoO), and the formation method is, for example, chemical vapor deposition or atomic layer deposition. In the present embodiment, the oxygen content of the variable resistance layer 104 can be about 75 atomic percent (at%) to about 100 atomic percent. The thickness of the variable resistance layer 104 is, for example, 2nm to 10nm.

[0013] The oxygen exchange layer 116a is located between the variable resistance layer 104 and the second electrode 120. The top area of ​​the oxygen exchange layer 116a is smaller than the bottom area of ​​the second electrode 120, and the bottom area of ​​the oxygen exchange layer 116a is smaller than the top area of ​​the variable resistance layer 104. The oxygen exchange layer 116a may be a material that is easier to bond with oxygen than the vacant drive electrode layer 110 and the variable resistance layer 104. The material of the oxygen exchange layer 116a may include an incompletely oxidized metal oxide. In other words, the oxygen exchange layer 116a itself is a metal layer containing oxygen ions. In this embodiment, the material of the oxygen exchange layer 116a may include, for example, TiO 2-x , HfO 2-x or TaO 2-x , wherein x is 0.2 to 0.7. The oxygen exchange layer 116a is formed by, for example, chemical vapor deposition or atomic layer deposition.

[0014] The first oxygen barrier layer 114a and the second oxygen barrier layer 118 surround and cover the top surface and upper sidewall of the oxygen exchange layer 116a. The first oxygen barrier layer 114a laterally surrounds the upper sidewall of the oxygen exchange layer 116a, and is located between the second oxygen barrier layer 118 and the vacancy supply layer 108, and between the upper sidewall of the oxygen exchange layer 116a and the vacant driving electrode layer 110. The second oxygen barrier layer 118 covers the top surface of the oxygen exchange layer 116a, the top surface of the first oxygen barrier layer 114a, and the top surface of the vacant driving electrode layer 110. In this embodiment, when the RRAM cell 10 performs a RESET operation, the first oxygen barrier layer 114a and the second oxygen barrier layer 118 can prevent oxygen ions in the oxygen exchange layer 116a from diffusing to the second electrode 120 and the vacant driving electrode layer 110. The first oxygen barrier layer 114 a and the second oxygen barrier layer 118 may include a high dielectric constant dielectric material layer having a dielectric constant greater than 3, such as aluminum oxide (Al 2 O 3 ), hafnium oxide (HfO 2 ), zirconium oxide (ZrO 2 ) or a combination thereof.

[0015] The vacancy providing layer 108 laterally surrounds the middle sidewall of the oxygen exchange layer 116a, and can provide vacancies to the oxygen exchange layer 116a. The material of the vacancy providing layer 108 may include an incompletely oxidized metal oxide. In other words, the vacancy providing layer 108 itself is a metal layer containing oxygen ions. The material of the vacancy providing layer 108 may include TiO x 、TaO x , HfO x 、Ta2O 5-x or TaO 2-x , wherein x is 0.2 to 1.8, and the thickness is, for example, 5 nm to 50 nm. The vacancy-providing layer 108 is formed by, for example, chemical vapor deposition or atomic layer deposition.

[0016] The vacancy driving electrode layer 110 is located above the vacancy providing layer 108 and below the second electrode 120, and is spaced apart from the first oxygen barrier layer 114a and laterally surrounds the upper side wall of the oxygen exchange layer 116a. The vacancy driving electrode layer 110 can drive the vacancies in the vacancy providing layer 108 below, so that the vacancies enter the oxygen exchange layer 116a through the middle side wall of the oxygen exchange layer 116a. Compared with the oxygen exchange layer 116a and the vacancy providing layer 108, the vacancy driving electrode layer 110 is less likely to bond with oxygen. The vacancy driving electrode layer 110 can also be called an inert vacancy driving electrode layer 110. The vacancy driving electrode layer 110 can be a single layer or a multilayer. The vacancy driving electrode layer 110 includes a conductive material. The conductor material may be a metal or a metal nitride, such as platinum, iridium, ruthenium, rhodium, tungsten, titanium, hafnium, tantalum, hafnium nitride, tantalum nitride, titanium nitride, tungsten nitride, or a combination thereof, and the formation method may be, for example, physical vapor deposition. In one embodiment, the top surface of the vacant driving electrode layer 110 is coplanar with the top surface of the first oxygen barrier layer 114a and the top surface of the oxygen exchange layer 116a. The bottom surface of the vacant driving electrode layer 110 is coplanar with the bottom surface of the first oxygen barrier layer 114a. The thickness of the vacant driving electrode layer 110 is, for example, 10 nm to 100 nm.

[0017] The vacancy blocking layer 106 is located below the vacancy providing layer 108 and above the variable resistance layer 104, and laterally surrounds the lower sidewall of the oxygen exchange layer 116a. The vacancy blocking layer 106 can block the vacancies in the vacancy providing layer 108 from diffusing downward, and limit the path of the vacancies in the vacancy providing layer 108. The path of the vacancies in the vacancy providing layer 108 is to enter the oxygen exchange layer 116a through the middle sidewall of the oxygen exchange layer 116a, and then go down to the variable resistance layer 104. The material of the vacancy blocking layer 106 includes a dielectric material. The dielectric constant of the vacancy blocking layer 106 is greater than 4 and less than the dielectric constants of the first oxygen blocking layer 114a and the second oxygen blocking layer 118. The dielectric material is, for example, a dielectric material containing silicon. The dielectric material containing silicon is, for example, silicon nitride, silicon carbide, or a combination thereof. The silicon-containing dielectric material is, for example, silicon nitride, silicon carbide, silicon carbonitride (SiCN), silicon carbon oxynitride (SiCON), or a combination thereof. The vacancy blocking layer 106 is formed by, for example, chemical vapor deposition or atomic layer deposition.

[0018] When the RRAM cell 10 is in a forming operation, a positive voltage is applied to the second electrode 120, so that the oxygen ions in the variable resistance layer 104 are attracted by the positive voltage to leave the variable resistance layer 104 and enter the oxygen exchange layer 116a, and generate oxygen vacancies in the variable resistance layer 104, thereby forming a filament current. In addition, when a positive voltage is applied to the second electrode 120, the vacancy driving electrode layer 110 also drives the vacancies in the vacancy supply layer 108 below to enter the oxygen exchange layer 116a through the middle sidewall of the oxygen exchange layer 116a, and then go down to the variable resistance layer 104, thereby forming an additional filament current. In other words, the current of the RRAM cell 10 not only comes from the vacancies formed by the oxygen ions leaving the variable resistance layer 104 itself, but also includes the vacancies in the vacancy supply layer 108, so the RRAM cell 10 has a sufficient current.

[0019] The manufacturing method of the RRAM cell 10 can refer to Figures 1A to 1G The description is as follows. In this document, the same or similar components use the same or similar reference numerals and can be formed by the same material or method. For example, the components of the first electrode layers 102 and 102a can be formed by the same material or method.

[0020] Reference Figure 1A A first electrode layer 102, a variable resistance layer 104, a vacancy blocking layer 106, a vacancy providing layer 108 and a vacancy driving electrode layer 110 are sequentially formed on a substrate (not shown) on which a via plug 100 and a dielectric layer 99 have been formed.

[0021] Reference Figure 1B , photolithography and etching processes are performed to pattern the vacant driving electrode layer 110, and then an opening 112 is formed in the vacant driving electrode layer 110. The bottom surface of the opening 112 exposes the vacancy providing layer 108.

[0022] Reference Figure 1C , forming a first oxygen barrier layer 114 in the opening 112. The first oxygen barrier layer 114 is formed by, for example, forming a first oxygen barrier material layer on the vacant driving electrode layer 110 and in the opening 112, and then performing a planarization process to remove the first oxygen barrier material layer outside the opening 112. The planarization process is, for example, an etch-back process or a chemical mechanical polishing process.

[0023] Reference Figure 1D, an opening 115 is formed in the first oxygen barrier layer 114, the vacancy supply layer 108 and the vacancy barrier layer 106, and the first oxygen barrier layer 114a is left on the upper sidewall of the opening 115. The method for forming the opening 115 can adopt photolithography and etching methods to pattern the first oxygen barrier layer 114, the vacancy supply layer 108 and the vacancy barrier layer 106. The opening 115 can also be formed by the following method. An anisotropic etching process is performed on the first oxygen barrier layer 114 to form an oxygen blocking spacer, that is, the first oxygen barrier layer 114a. Thereafter, an etching process is performed using the oxygen blocking spacer (first oxygen barrier layer 114a) and the vacancy driving electrode layer 110 as a hard mask to remove part of the vacancy supply layer 108 and part of the vacancy barrier layer 106 to form the opening 115.

[0024] Reference Figure 1E and Figure 1F , an oxygen exchange layer 116 is formed on the vacant driving electrode layer 110 and the first oxygen barrier layer 114a and in the opening 115. Then, a planarization process is performed to remove the oxygen exchange layer 116 outside the opening 115, so that the oxygen exchange layer 116 remains in the opening 115 and the vacant driving electrode layer 110 and the first oxygen barrier layer 114a are exposed. The planarization process is, for example, an etch-back process or a chemical mechanical polishing process.

[0025] Reference Figure 1G , a second oxygen barrier layer 118 and a second electrode layer 120 are formed on the vacancy driving electrode layer 110 and the first oxygen barrier layer 114a. Then, the second electrode layer 120, the second oxygen barrier layer 118, the vacancy driving electrode layer 110, the vacancy supply layer 108, the vacancy barrier layer 106, the variable resistance layer 104 and the first electrode layer 102 are subjected to the treatment to form a resistance random access memory cell 10.

[0026] The resistance random access memory and the manufacturing method thereof of the embodiment of the present invention can increase the vacancies of the variable resistance layer by setting the vacant driving electrode layer and the vacant providing layer, thereby increasing the current of the resistance random access memory, avoiding the use of excessive operating voltage, and reducing power consumption. In addition, since the resistance random access memory has a high current in the initial stage, even if part of the filaments are damaged in the subsequent baking process, the resistance random access memory can still have sufficient current during operation.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resistance random access memory, characterized in that: include: The first electrode layer and the second electrode layer are arranged opposite to each other; a variable resistance layer, located between the first electrode layer and the second electrode layer; an oxygen exchange layer, located between the variable resistance layer and the second electrode layer; a vacancy providing layer located around the middle side wall surrounding the oxygen exchange layer; and The vacancy driving electrode layer is located on the vacancy providing layer and surrounds the upper side wall of the oxygen exchange layer.

2. The resistance random access memory according to claim 1, wherein the material of the vacancy providing layer comprises TiO x 、TaO x , HfO x 、Ta2O 5-x or TaO 2-x , where x is from 0.2 to 1.

8.

3. The resistance random access memory according to claim 1, wherein the material of the vacant driving electrode layer comprises platinum, iridium, ruthenium, rhodium, tungsten, titanium, hafnium, tantalum, hafnium nitride, tantalum nitride, titanium nitride, tungsten nitride, or a combination thereof. 4 . The resistance random access memory according to claim 1 , further comprising a vacancy blocking layer located between the variable resistance layer and the vacancy providing layer and surrounding a lower sidewall of the oxygen exchange layer.

5. The resistance random access memory according to claim 1, further comprising: A first oxygen blocking layer is located between the upper side wall of the oxygen exchange layer and the vacant driving electrode layer; as well as The second oxygen blocking layer is located between the second electrode layer and the vacant driving electrode layer and between the second electrode layer and the oxygen exchange layer.

6. A method for manufacturing a resistance random access memory, characterized in that: include: forming a variable resistance layer on the first electrode layer; forming a vacancy providing layer on the variable resistance layer; forming a vacancy driving electrode layer on the vacancy providing layer; forming a first opening in the vacant driving electrode layer; forming a first oxygen barrier layer in the first opening; forming a second opening in the first oxygen barrier layer and the vacancy-providing layer; forming an oxygen exchange layer in the second opening; forming a second oxygen barrier layer on the vacant driving electrode layer and the oxygen exchange layer; and A second electrode layer is formed on the second oxygen barrier layer.

7. The method for manufacturing a resistance random access memory according to claim 6, wherein the material of the vacancy providing layer comprises TiO x 、TaO x , HfO x 、Ta2O 5-x or TaO 2-x , where x is from 0.2 to 1.

8.

8. The method for manufacturing a resistance random access memory according to claim 6, wherein the material of the vacant driving electrode layer comprises platinum, iridium, ruthenium, rhodium, tungsten, titanium, hafnium, tantalum, hafnium nitride, tantalum nitride, titanium nitride, tungsten nitride, or a combination thereof. 9 . The method for manufacturing a resistance random access memory according to claim 6 , further comprising forming a vacancy blocking layer on the variable resistance layer before forming the vacancy providing layer on the variable resistance layer.

10. The method for manufacturing a resistive random access memory according to claim 9, wherein the method for forming the second opening in the first oxygen barrier layer, the vacancy supply layer and the vacancy barrier layer comprises performing photolithography and etching processes to pattern the first oxygen barrier layer, the vacancy supply layer and the vacancy barrier layer.

11. The method for manufacturing a resistance random access memory according to claim 10, wherein a method of forming the second opening in the first oxygen barrier layer, the vacancy-providing layer, and the vacancy barrier layer comprises: performing an anisotropic etching process on the first oxygen blocking layer to form an oxygen blocking spacer; as well as An etching process is performed using the oxygen blocking spacer and the vacancy driving electrode layer as a hard mask to remove a portion of the vacancy providing layer and a portion of the vacancy blocking layer.

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