Method for forming nickel silicide and semiconductor device

Abstract

The present application discloses a method for forming nickel silicide and a semiconductor device. The method for forming nickel silicide includes: providing a substrate formed with a gate, a source and a drain; and forming a nickel silicide having a sandwich structure on the surface of the gate, the source and the drain of the substrate, wherein the sandwich structure of the nickel silicide includes a nickel silicon film and an alloy layer located at the top and the bottom of the nickel silicon film. Through the scheme of the present application, the structure of the traditional nickel silicide is changed to form a nickel silicide having a nickel silicon film and an alloy layer on the gate, the source and the drain of the substrate, so that the nickel silicide can prevent the nickel in the nickel silicon film from diffusing outward at high temperature through the alloy layer located at the top and the bottom of the nickel silicon film, thereby improving the thermal stability of the nickel silicide.

Description

Technical Field

[0001] The present invention generally relates to the field of semiconductor manufacturing technology, and more specifically, to a method for forming nickel silicide and a semiconductor device. Background Art

[0002] Self-aligned silicide technology is a process technology that forms a metal silicide layer on the surface of the source / drain and the gate to reduce the resistance of the gate and the source / drain. In the related art, NiSi, compared with other traditional self-aligned silicide materials, not only has the advantages of low silicon consumption and low formation thermal budget of the silicide formation process, but also has the advantages of low resistivity and no line width effect. Therefore, NiSi has received extensive attention and research as the most promising self-aligned silicide material for nano-sized devices. Studies have found that under the current manufacturing process of integrated circuits or semiconductor devices, the thermal instability of NiSi films will be a huge obstacle to their manufacturability. In particular, the degradation of NiSi films will seriously affect the metal semiconductor contact characteristics, causing the contact resistance to increase sharply, thereby causing the device performance to decline.

[0003] Figure 1 The schematic diagram of the structure of a semiconductor device with a NiSi film in the related art is shown. As shown in the figure, the semiconductor device includes a substrate 101 and a nickel silicide (i.e., a NiSi film 102) formed on the substrate. The NiSi film 102 in the semiconductor device has poor thermal stability. Specifically, the Ni (i.e., Figure 1 The small black dots in the figure are very active at high temperatures, and the diffusion speed is significantly accelerated, which makes the thermal stability of the NiSi film 102 poor, resulting in a decrease in device performance, which is undoubtedly a fatal blow to ultra-shallow junction and short channel devices.

[0004] In view of this, there is an urgent need to provide a nickel silicide formation solution to effectively improve the thermal stability of nickel silicide. Summary of the invention

[0005] In order to at least solve one or more of the technical problems mentioned above, the present application proposes a solution for forming nickel silicide in multiple aspects.

[0006] In a first aspect, the present application provides a method for forming nickel silicide, comprising: providing a substrate having a gate, a source and a drain formed thereon; and forming a nickel silicide having a sandwich structure on the surfaces of the gate, the source and the drain of the substrate, wherein the sandwich structure of the nickel silicide comprises a nickel silicon thin film and an alloy layer located at the top and bottom of the nickel silicon thin film, and the lattice constant of the metal in the alloy layer is smaller than the lattice constant of the nickel in the nickel silicon thin film.

[0007] In some embodiments, forming a nickel silicide having a sandwich structure on the surfaces of the gate, source and drain of the substrate includes: sequentially forming a first nickel layer, a first metal layer, a second metal layer and a second nickel layer on the surfaces of the gate, source and drain of the substrate; and using a rapid thermal annealing process to process the substrate and the first nickel layer, the first metal layer, the second metal layer and the second nickel layer on the substrate to obtain the nickel silicide.

[0008] In some embodiments, the alloy layer comprises a hafnium-tantalum alloy layer.

[0009] In some embodiments, the first metal layer includes a hafnium layer, and the second metal layer includes a tantalum layer.

[0010] In some embodiments, sequentially forming a first nickel layer, a first metal layer, a second metal layer, and a second nickel layer includes: using a physical vapor deposition process to deposit nickel on the surfaces of the gate, source, and drain of the substrate to obtain the first nickel layer; and in an inert gas environment, sequentially depositing hafnium, tantalum, and nickel on the first nickel layer to obtain the hafnium layer, tantalum layer, and second nickel layer.

[0011] In some embodiments, the substrate and the first nickel layer, the first metal layer, the second metal layer and the second nickel layer on the substrate are processed using a rapid thermal annealing process, including: performing a first rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate to obtain the nickel silicon thin film; and performing a second rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate to allow the hafnium layer and the tantalum layer to diffuse evenly from top to bottom to the top and bottom of the nickel silicon thin film, and to form the hafnium tantalum alloy layer on the top and bottom of the nickel silicon thin film.

[0012] In some embodiments, performing a first rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate includes: performing a rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate at an annealing temperature of 500°C to 600°C in a nitrogen environment.

[0013] In some embodiments, performing a second rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate includes: performing a rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate at an annealing temperature of 600°C to 900°C.

[0014] In some embodiments, the mass ratio of hafnium in the hafnium layer to tantalum in the tantalum layer is 3:5.

[0015] In a second aspect, the present application provides a semiconductor device, comprising: a substrate; wherein a gate structure is formed on the surface of the substrate, a source and a drain are formed in the substrate on both sides of the gate structure, and nickel silicide is formed on the surface of the gate structure and the surfaces of the source and drain, and the nickel silicide is formed using the method for forming nickel silicide as described in the first aspect above.

[0016] The unexpected beneficial technical effect of the present application is: through the method for forming nickel silicide and the semiconductor device provided above, the embodiment of the present application forms a nickel silicide with a sandwich structure on a substrate formed with a gate, a source and a drain, and forms a diffusion barrier through the alloy layer located at the top and bottom of the nickel silicon film in the nickel silicide, the lattice constant of the metal in the alloy layer is smaller than the lattice constant of the nickel in the nickel silicon film, so that the interaction force between the atoms of the metal in the alloy is stronger than the interaction force between the nickel atoms, and it is difficult for nickel to break through the alloy layer and diffuse outward at high temperature, thereby preventing nickel (Ni) in the nickel silicon film from diffusing outward at high temperature based on the diffusion barrier. It can be seen that the scheme of the present application can improve the thermal stability of nickel silicide by avoiding nickel diffusion, thereby effectively avoiding the influence of nickel diffusion on device performance.

[0017] Furthermore, in some embodiments, the solution of the present application forms nickel silicide by sequentially depositing nickel, hafnium, tantalum and nickel, so that dislocation is not easy to occur during the formation of nickel silicide, and hafnium and tantalum can be uniformly diffused to the top and bottom of the nickel silicon film. In addition, hafnium and tantalum are used to form a hafnium-tantalum alloy layer as a diffusion barrier for nickel on the top and bottom of the nickel silicon film, which can effectively control the cost compared with other precious metal materials.

[0018] Furthermore, in the process of forming nickel silicide, by controlling the mass ratio between hafnium and tantalum, the transformation of NiSi to NiSi2 can be effectively suppressed, and the creep performance of the nickel silicon film in the nickel silicide can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become easy to understand. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0020] Figure 1 A cross-sectional schematic diagram of a semiconductor device structure formed with nickel silicide in the related art is shown;

[0021] Figure 2 A schematic diagram of the cross-sectional structure of nickel silicide according to an embodiment of the present application is shown;

[0022] Figure 3 A schematic flow chart showing a method for forming nickel silicide of a semiconductor device according to some embodiments of the present application;

[0023] Figure 4 A schematic flow chart showing a method for forming nickel silicide of a semiconductor device according to other embodiments of the present application;

[0024] Figure 5a and Figure 5b A cross-sectional schematic diagram showing related devices in a nickel silicide formation process using some embodiments of the present application; and

[0025] Figure 6 A cross-sectional schematic diagram of a semiconductor device using an embodiment of the present application is shown.

[0026] Among them, the markings in the accompanying drawings are as follows:

[0027] 101-substrate, 102-NiSi film, 201-substrate, 202-nickel silicide, 2021-nickel silicon film, 2022-alloy layer, 501-substrate, 502-first nickel layer, 503-hafnium layer, 504-tantalum layer, 505-second nickel layer, 506-nickel silicide, 5061-nickel silicon film, 5062-hafnium tantalum alloy layer, 600-semiconductor device, 601-substrate, 602-gate structure, 603-sidewall structure, 604-shallow trench isolation, 605-nickel silicide. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0029] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this application specification and claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms. It should also be further understood that the term "and / or" used in this application specification and claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0031] In the related technology, nickel silicon film (NiSi) can be used as self-aligned silicide. However, in practical applications, the thermal instability of this NiSi film will affect the device performance and bring huge obstacles to the manufacturability of the device. Studies have found that there are two degradation mechanisms of NiSi film at high temperature: phase transition from low resistivity phase (NiSi) to high resistivity phase (NiSi2) and agglomeration of film at high temperature. Among them, the degradation of NiSi film will seriously affect the contact characteristics of metal semiconductors, causing the contact resistance to increase sharply, thereby causing the device performance to decline. In addition, it was found that Ni is very active at high temperatures and the diffusion rate is significantly accelerated, which is undoubtedly a fatal blow to ultra-shallow junction and short channel devices.

[0032] In order to solve the problem in the above scenario, the inventors proposed a nickel silicide formation scheme, which can form a nickel silicide with a sandwich structure, so as to prevent the nickel (Ni) in the nickel silicon film from diffusing outward at high temperature through the alloy layer in the sandwich structure, thereby improving the thermal stability of the nickel silicide.

[0033] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0034] Figure 2 A cross-sectional schematic diagram of the structure of nickel silicide according to an embodiment of the present application is shown.

[0035] like Figure 2As shown, nickel silicide 202 can be formed on the surface of substrate 201. Specifically, a gate, a source and a drain are formed on the substrate, and the nickel silicide 202 is formed on the surface of the gate, the source and the drain of the substrate 201. The nickel silicide 202 is a sandwich structure, and the sandwich structure of the nickel silicide 202 specifically includes a nickel silicon film 2021 and an alloy layer 2022 located at the top and bottom of the nickel silicon film 2021. The substrate 201 in this embodiment can be a substrate that has a self-aligned silicide formation requirement in the manufacturing process of an integrated circuit or a semiconductor device, for example, a silicon substrate, a germanium silicon substrate or other substrates containing silicon materials known to those skilled in the art can be used. It should be noted that the substrate in this embodiment can be formed by conventional or known processes, and the specific structure and formation details of the substrate will not be repeated in the solution of this application. In addition, a gate, a source and a drain can be formed on the surface of the substrate by conventional or known processes.

[0036] In some embodiments, the nickel silicide in this embodiment can be formed by sequentially depositing nickel, hafnium, tantalum and nickel on a substrate, and combining a rapid thermal annealing process. The hafnium-tantalum alloy layer 2022 located at the top and bottom of the nickel silicon film 2021 can prevent the nickel in the nickel silicon film 2021 from diffusing outward at high temperatures.

[0037] Different from the conventional technology in which nickel silicide as self-aligned silicide only includes nickel silicon film, the unexpected beneficial technical effect of the present application is that nickel silicide with a sandwich structure can be formed on a substrate containing silicon, and a diffusion barrier is formed by the alloy layer at the top and bottom of the nickel silicon film in the nickel silicide, so as to prevent nickel (Ni) in the nickel silicon film from diffusing outward at high temperature based on the diffusion barrier. Thus, the thermal stability of nickel silicide can be improved by preventing nickel diffusion, thereby effectively preventing nickel diffusion from affecting device performance.

[0038] Figure 3 1 is a schematic flow chart of a method 300 for forming nickel silicide according to some embodiments of the present application. It should be noted that: Figure 3 It can be understood that Figure 2 An exemplary preparation process of nickel silicide, Figure 2 The relevant instructions in also apply to the following.

[0039] like Figure 3As shown, at step S301, a substrate having a gate, a source and a drain formed thereon may be provided. It should be noted that the present embodiment does not limit the specific type and specific structure of the substrate, and may include a substrate containing silicon and requiring the layout of self-aligned silicide in the process of manufacturing an integrated circuit or a semiconductor device. In some embodiments, the substrate may include a silicon substrate, a germanium silicon substrate or other substrate containing silicon materials, for example, a silicon substrate in a transistor device such as a metal oxide semiconductor field effect transistor (MOS), a complementary metal oxide semiconductor (CMOS), or an N-type metal-oxide-semiconductor (N-Metal-Oxide-Semiconductor, NMOS). In addition, a gate, a source and a drain may be formed on the above substrate using conventional processes or known processes.

[0040] In step S302, nickel silicide having a sandwich structure may be formed on the surfaces of the gate, source and drain of the substrate, wherein the sandwich structure of the nickel silicide includes a nickel silicon film and alloy layers located on the top and bottom of the nickel silicon film.

[0041] In this embodiment, after a substrate having a gate, a source and a drain formed thereon is obtained by using an existing or conventional process, a nickel material may be added to the surface of the gate, the source and the drain of the substrate to generate a nickel silicon film by reacting the nickel material with the silicon material on the surface of the gate, the source and the drain, and a first metal material and a second metal material may be added to the surface of the gate, the source and the drain of the substrate, and the two metal materials are diffused to the top and the bottom of the nickel silicon film to form an alloy layer. Thus, a nickel silicide having a sandwich structure may be obtained.

[0042] Among them, the crystal constant of the metal in the alloy layer is less than the lattice constant of nickel. Generally, the size of the lattice constant has an important influence on the physical and chemical properties of the crystal. The smaller the lattice constant, the closer the distance between atoms in the crystal, the stronger the interaction between atoms, and the higher the hardness and melting point of the crystal. The larger the lattice constant, the farther the distance between atoms in the crystal, the weaker the interaction between atoms, and the lower the hardness and melting point of the crystal. As a result, the lattice constant of the metal in the alloy layer is less than the lattice constant of nickel in the nickel-silicon film, so that the interaction between the atoms of the metal in the alloy is stronger than the interaction between nickel atoms, and it is difficult for nickel to break through the alloy layer and diffuse outward at high temperatures. In this example, the first metal layer and the second metal layer in the alloy layer can adopt any material with a lattice constant less than nickel. Preferably, the alloy layer can adopt a hafnium-tantalum alloy layer, and the first metal layer adopts a hafnium layer and the second metal layer adopts a tantalum layer.

[0043] The unexpected beneficial technical effect of the present application is: by changing the structure of the traditional nickel silicide, a nickel silicide having a nickel silicon film and a hafnium tantalum alloy layer is formed on a silicon-containing substrate, so that the nickel silicide in the present application can block the nickel in the nickel silicon film from diffusing outward at high temperature through the hafnium tantalum alloy layer located at the top and bottom of the nickel silicon film, thereby improving the thermal stability of the nickel silicide. In addition, the use of the hafnium tantalum alloy layer as a diffusion barrier to block the diffusion of nickel can have both low cost and better prevention of nickel diffusion compared to the use of hafnium or tantalum alone as a diffusion barrier. At the same time, the appropriate adjustment of the ratio of hafnium material and tantalum material can also improve the creep performance of the nickel silicon film. In addition, compared with some other high-cost precious metals (such as platinum, etc.), the cost of hafnium materials and tantalum materials is relatively low, which can effectively control costs.

[0044] Figure 4 4 shows a schematic flow chart of a method 400 for forming nickel silicide according to another embodiment of the present application. It should be noted that: Figure 4 It can be understood that Figure 3 Therefore, the above combined with Figure 3 The relevant description also applies to the following.

[0045] like Figure 4 As shown, at step S401, a substrate having a gate, a source and a drain formed thereon may be provided. In this embodiment, the substrate may be obtained by conventional or known preparation processes, and the substrate may include, for example, a silicon substrate in a transistor device such as NMOS or other substrates containing silicon materials.

[0046] After obtaining the above-mentioned substrate, a nickel silicide having a sandwich structure can be formed on the surface of the substrate. It should be noted that the present application does not limit the specific formation position of the nickel silicide on the substrate, and the specific formation position of the nickel silicide on the substrate can be set according to process requirements and device design requirements. For example, when preparing a semiconductor device, a gate, a source, a drain, a sidewall structure, etc. can be formed on the substrate, and the nickel silicide can be specifically formed in the surface area of ​​the gate, the source, and the drain.

[0047] In practical applications, the nickel silicide with a sandwich structure can be formed on the surface of the gate, source and drain of the substrate in a variety of ways. In some embodiments, a first nickel layer, a hafnium layer, a tantalum layer and a second nickel layer can be formed on the surface of the aforementioned substrate in sequence, and the substrate and the first nickel layer, hafnium layer, tantalum layer and the second nickel layer on the substrate can be processed by a rapid thermal annealing process to obtain nickel silicide. In this embodiment, materials such as nickel, hafnium, tantalum and nickel can be added in sequence according to the contact order with the silicon on the surface of the substrate to form a first nickel layer, a hafnium layer, a tantalum layer and a second nickel layer, and then different rapid thermal annealing process conditions can be set to first react the nickel material with the silicon on the surface of the substrate to form a nickel silicon film through multiple rapid thermal annealing treatments, and then the hafnium material and tantalum are diffused upward and downward to form a hafnium tantalum alloy layer on the top and bottom of the nickel silicon film, thereby obtaining a nickel silicide with a sandwich structure.

[0048] As an example, Figure 4 Steps S402 to S405 in the figure exemplify the specific formation process of a sandwich structure of a nickel silicide body. Specifically, in step S402, nickel can be deposited on the surface of the substrate using a physical vapor deposition (PVD) process to obtain a first nickel layer. This embodiment does not limit the thickness of the first nickel layer, which can be adjusted according to the process and device design requirements. Next, in step S403, hafnium, tantalum and nickel can be deposited on the first nickel layer in sequence in an inert gas (such as argon) environment to obtain a hafnium layer, a tantalum layer and a second nickel layer.

[0049] This embodiment has certain requirements for the order of adding materials such as hafnium, tantalum and nickel. Generally, there are differences in the lattice constants of hafnium, tantalum and nickel, and the lattice constant of nickel is greater than the lattice constant of tantalum and greater than the crystal constant of hafnium. Therefore, after forming the first nickel layer, it is necessary to first deposit a layer of hafnium, then a layer of tantalum, and finally a layer of nickel. The nickel in the obtained second nickel layer exerts a compressive stress on the tantalum in the tantalum layer, and the tantalum in the tantalum layer exerts a compressive stress on the hafnium in the hafnium layer, so that both hafnium and tantalum are subjected to compressive stress, thereby making it difficult for the hafnium layer and the tantalum layer to be dislocated.

[0050] See also Figure 5a, the substrate 501 is a substrate containing silicon on the surface, and nickel material, hafnium material, tantalum material and nickel material can be deposited in sequence on the substrate 501 to form a first nickel layer 502, a hafnium layer 503, a tantalum layer 504 and a second nickel layer 505. It should be noted that the scheme of the present application does not limit the specific dimensions (such as thickness, etc.) of the first nickel layer 502, the hafnium layer 503, the tantalum layer 504 and the second nickel layer 505, which can be set and adjusted in combination with the preparation process and device design requirements.

[0051] In addition, it should be noted that the scheme of the present application preferably adopts the above-mentioned material addition order to obtain the first nickel layer 502, the hafnium layer 503, the tantalum layer 504 and the second nickel layer 505 to avoid dislocation. Of course, in other embodiments, the order of adding materials can also be adjusted to obtain a nickel silicide with a sandwich structure. For example, nickel material, tantalum material, hafnium material and nickel material can be deposited on the substrate in sequence to form a first nickel layer, a tantalum layer, a hafnium layer and a second nickel layer. It should be noted that in this scenario, because the nickel in the second nickel layer exerts compressive stress on the hafnium in the hafnium layer, and the hafnium in the hafnium layer exerts tensile stress on the tantalum in the tantalum layer, the hafnium layer and the tantalum layer are prone to dislocation, and the performance of the nickel silicide finally formed may not be utilized. Figure 5a The nickel silicide produced by the material addition sequence shown has good performance.

[0052] Furthermore, in some embodiments, during the addition of the hafnium material and the tantalum material, the relative ratio of the hafnium material and the tantalum material can be adjusted. For example, the mass ratio of hafnium in the hafnium layer to tantalum in the tantalum layer can be controlled to be 3:5, so as to effectively inhibit the transformation of NiSi into NiSi2 and significantly improve the creep performance of the nickel silicon film in the nickel silicide.

[0053] After forming a first nickel layer, a hafnium layer, a tantalum layer and a second nickel layer on the surface of the substrate, returning Figure 4 At step S404, the substrate and the first nickel layer, hafnium layer, tantalum layer and second nickel layer on the substrate may be subjected to a first rapid thermal annealing treatment to obtain a nickel silicon film. In some embodiments, the substrate and the first nickel layer, hafnium layer, tantalum layer and second nickel layer on the substrate may be subjected to a rapid thermal annealing treatment at a first temperature annealing temperature in a nitrogen environment. At the first temperature (e.g., 500°C to 600°C) annealing temperature, silicon on the surface of the substrate diffuses and reacts with nickel in the first nickel layer and the second nickel layer, and after a period of time (e.g., 50s), a nickel silicon film may be formed.

[0054] Next, at step S405, a second rapid thermal annealing treatment may be performed on the substrate and the first nickel layer, hafnium layer, tantalum layer and second nickel layer on the substrate, so that the hafnium layer and tantalum layer diffuse evenly from top to bottom to the top and bottom of the nickel silicon film, and a hafnium tantalum alloy layer is formed on the top and bottom of the nickel silicon film. That is, after the nickel silicon film is obtained by the first rapid thermal annealing treatment, the second rapid thermal annealing treatment may be continued. It should be noted that the conditions of the second rapid thermal annealing treatment are different from those of the first thermal annealing treatment. The second rapid thermal annealing treatment needs to ensure that hafnium and tantalum can diffuse into the nickel silicon film, while the first rapid thermal annealing treatment needs to ensure that nickel and silicon can be combined into a nickel silicon film.

[0055] Specifically, in some embodiments, the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate may be subjected to rapid thermal annealing at a second temperature annealing temperature, that is, the material structure obtained after the first rapid thermal annealing needs to be subjected to a second rapid thermal annealing treatment. At the second temperature (e.g., 600°C to 900°C) annealing temperature, the hafnium layer and the tantalum layer diffuse upward and downward to the top and bottom of the nickel silicon film to form a uniformly distributed hafnium-tantalum alloy layer at the top and bottom of the nickel silicon film, and the hafnium-tantalum alloy layer may serve as a diffusion barrier to prevent the diffusion of Ni atoms in the nickel silicon film.

[0056] See also Figure 5b The substrate 501 is a substrate containing silicon on its surface. Figure 5a In the order of adding materials shown, nickel material, hafnium material, tantalum material and nickel material are sequentially deposited on the substrate 501 to form a first nickel layer 502, a hafnium layer 503, a tantalum layer 504 and a second nickel layer 505. Next, the substrate 501 and the first nickel layer 502, the hafnium layer 503, the tantalum layer 504 and the second nickel layer 505 on the substrate 501 are subjected to a first rapid thermal annealing treatment at an annealing temperature of, for example, 500° C. to 600° C. in a nitrogen environment. At this time, silicon on the surface of the substrate diffuses and reacts with nickel in the first nickel layer and the second nickel layer. After a period of time, a nickel-silicon film 5061 can be formed. Then, the substrate 501 and the first nickel layer 502, the hafnium layer 503, the tantalum layer 504 and the second nickel layer 505 on the substrate 501 can be subjected to a second rapid thermal annealing treatment at an annealing temperature of, for example, 600°C to 900°C, so that the hafnium layer 503 and the tantalum layer 504 diffuse upward and downward to the top and bottom of the nickel silicon film 5061, so as to form a uniformly distributed hafnium tantalum alloy layer 5062 on the top and bottom of the nickel silicon film 5061, thereby obtaining a nickel silicide 506 with a sandwich structure. It should be noted that the detailed description of the rapid thermal annealing process here is only an exemplary description, and the solution of the present application is not limited to this, and it can be specifically set and adjusted in combination with actual process requirements.

[0057] The unexpected beneficial technical effect of the present application is: nickel silicide is formed by sequentially depositing nickel, hafnium, tantalum and nickel on the surface of a substrate containing silicon, so that dislocation is not easy to occur during the formation of nickel silicide, and hafnium and tantalum can be ensured to be uniformly diffused to the top and bottom of the nickel silicon film. In addition, hafnium and tantalum are used to form a hafnium-tantalum alloy layer as a diffusion barrier for nickel at the top and bottom of the nickel silicon film, which can effectively control the cost compared with other precious metal materials. In addition, in the process of forming nickel silicide, by controlling the mass ratio between hafnium and tantalum, the transformation of NiSi to NiSi2 can be effectively suppressed, and the creep performance of the nickel silicon film in the nickel silicide can be significantly improved. That is, the scheme of the present application can effectively improve the thermal stability and creep performance of the nickel silicon film in the nickel silicide by improving the structure of nickel silicide, while avoiding the diffusion of Ni atoms in the nickel silicon film affecting the device performance.

[0058] It should be noted that the above Figure 3 , Figure 4 , Figure 5a as well as Figure 5b The described nickel silicide with sandwich structure can be applied to the preparation of integrated circuits or semiconductor devices. Figure 6 The cross-sectional schematic diagram of the semiconductor device 600 of the present application is shown. The semiconductor device 600 needs to use nickel silicide as the self-aligned silicide. Figure 3~Figure 5b The specific details of nickel silicide described above also apply below.

[0059] like Figure 6 As shown, the semiconductor device 600 includes a substrate 601, and the substrate 601 of the semiconductor device 600 is usually a silicon substrate or a substrate containing other silicon materials. A gate structure 602 is also formed on the surface of the substrate 601, and a source and a drain (not shown in the figure) are formed in the substrate on both sides of the gate structure, and nickel silicide 605 is formed on the surface of the gate structure 602 and the surface of the source and drain. In addition, sidewall structures 603 (for example, sidewalls of ONO structure can be used) are also formed on both sides of the gate structure 602, and shallow trench isolation (STI for short) 604 is also formed on the substrate 601.

[0060] It should be noted that the gate structure 602, source, drain, sidewall structure 603 and STI 604 in this embodiment can be formed by conventional or known processes, and the specific details of these structures will not be described in detail in the solution of this application.

[0061] The nickel silicide 605 can be specifically made of Figure 3~Figure 5bThe nickel silicide 605 may be prepared by the formation method described above, wherein the nickel silicide 605 may specifically include a nickel silicon film and a hafnium tantalum alloy layer located on the top and bottom of the nickel silicon film. In the process of forming the nickel silicide 605, it is preferred to form the nickel silicide by sequentially depositing nickel, hafnium, tantalum and nickel on the surfaces of the gate structure, the source and the drain, so that the hafnium layer and the tantalum layer are not prone to dislocation during the formation of the nickel silicide.

[0062] The unexpected beneficial technical effect of the present application is: by improving the structure of nickel silicide, a hafnium-tantalum alloy layer is formed on the top and bottom of the nickel-silicon film in the nickel silicide, and the hafnium-tantalum alloy layer located at the top and bottom of the nickel-silicon film is used to prevent the nickel in the nickel-silicon film from diffusing outward at high temperature, thereby improving the thermal stability of the nickel silicide. In addition, the use of the hafnium-tantalum alloy layer as a diffusion barrier to prevent nickel diffusion can have both low cost and better prevention of nickel diffusion. At the same time, the appropriate adjustment of the ratio of hafnium material to tantalum material can also improve the creep performance of the nickel-silicon film. In addition, compared with some other high-cost precious metals (such as platinum, etc.), the cost of hafnium materials and tantalum materials is relatively low, which can effectively control costs.

[0063] It should be noted that although the operations of the method of the present application are described in a specific order in the accompanying drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flow chart can be performed in a different order. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0064] Although multiple embodiments of the present application have been shown and described herein, it is obvious to those skilled in the art that such embodiments are provided only by way of example. Those skilled in the art can think of many changes, modifications and alternatives without departing from the thought and spirit of the present application. It should be understood that in the process of practicing the present application, various alternatives to the embodiments of the present application described herein can be adopted. The attached claims are intended to limit the scope of protection of the present application, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for forming nickel silicide, characterized in that: include: Providing a substrate having a gate, a source and a drain; as well as Forming a nickel silicide having a sandwich structure on the surface of the gate, source and drain of the substrate, wherein the sandwich structure of the nickel silicide includes a nickel silicon film and alloy layers located on the top and bottom of the nickel silicon film, and the lattice constant of the metal in the alloy layer is smaller than the lattice constant of the nickel in the nickel silicon film; The alloy layer in the sandwich structure is used to prevent nickel in the nickel-silicon film from diffusing outward at high temperature, and the alloy layer includes a hafnium-tantalum alloy layer.

2. The method for forming nickel silicide according to claim 1, characterized in that: Forming nickel silicide having a sandwich structure on the surfaces of the gate, source and drain of the substrate includes: forming a first nickel layer, a first metal layer, a second metal layer and a second nickel layer in sequence on the surfaces of the gate, the source and the drain of the substrate; and The substrate and the first nickel layer, the first metal layer, the second metal layer and the second nickel layer on the substrate are processed by a rapid thermal annealing process to obtain the nickel silicide.

3. The method for forming nickel silicide according to claim 2, characterized in that: The first metal layer includes a hafnium layer, and the second metal layer includes a tantalum layer.

4. The method for forming nickel silicide according to claim 3, characterized in that: Sequentially forming a first nickel layer, a first metal layer, a second metal layer, and a second nickel layer comprises: Depositing nickel on the surfaces of the gate, source and drain of the substrate using a physical vapor deposition process to obtain the first nickel layer; and In an inert gas environment, hafnium, tantalum and nickel are sequentially deposited on the first nickel layer to obtain the hafnium layer, the tantalum layer and the second nickel layer.

5. The method for forming nickel silicide according to claim 3, characterized in that: The method of using a rapid thermal annealing process to process the substrate and the first nickel layer, the first metal layer, the second metal layer, and the second nickel layer on the substrate includes: Performing a first rapid thermal annealing process on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate to obtain the nickel silicon thin film; and The substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate are subjected to a second rapid thermal annealing treatment so that the hafnium layer and the tantalum layer are uniformly diffused up and down to the top and bottom of the nickel silicon film, and the hafnium tantalum alloy layer is formed on the top and bottom of the nickel silicon film.

6. The method for forming nickel silicide according to claim 5, characterized in that: Performing a first rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer, and the second nickel layer on the substrate includes: The substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate are subjected to rapid thermal annealing treatment at an annealing temperature of 500° C. to 600° C. in a nitrogen environment.

7. The method for forming nickel silicide according to claim 5, characterized in that: Performing a second rapid thermal annealing treatment on the substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate comprises: The substrate and the first nickel layer, the hafnium layer, the tantalum layer and the second nickel layer on the substrate are subjected to rapid thermal annealing treatment at an annealing temperature of 600° C. to 900° C.

8. The method for forming nickel silicide according to claim 3, characterized in that: in, The mass ratio of hafnium in the hafnium layer to tantalum in the tantalum layer is 3:

5.

9. A semiconductor device, characterized in that: include: substrate; A gate structure is formed on the surface of the substrate, a source and a drain are formed in the substrate on both sides of the gate structure, and nickel silicide is formed on the surface of the gate structure and the surfaces of the source and the drain, and the nickel silicide is formed by the method for forming nickel silicide according to any one of claims 1 to 8; The alloy layer in the sandwich structure is used to prevent nickel in the nickel-silicon film from diffusing outward at high temperature, and the alloy layer includes a hafnium-tantalum alloy layer.

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