Method of fabricating a semiconductor structure

Abstract

The application provides a semiconductor structure manufacturing method, which comprises the following steps: providing a substrate; forming a first electrode layer on one side of the substrate; forming a dielectric layer on the surface of the first electrode layer far from the substrate; forming a second electrode layer on the surface of the dielectric layer far from the first electrode layer; performing chlorine removal pretreatment on the second electrode layer; and forming a third electrode layer on the surface of the second electrode layer far from the dielectric layer. The method solves the problem that chlorine ions at the junction of a silicon germanium layer in the prior art affect the interface reliability.

Description

Technical Field

[0001] This application relates to the field of semiconductor devices, and more specifically, to a method for fabricating a semiconductor structure. Background Technology

[0002] In current technologies, doped silicon-germanium layers exhibit relatively high mobility, relatively low resistivity, and low contact resistance, while maintaining the structure and composition of the deposited layer. Therefore, they can be used to fabricate the source and / or drain regions of semiconductor devices. However, during actual semiconductor device fabrication, impurities can be introduced at the junctions of the silicon-germanium layers, thereby affecting the reliability of the semiconductor device interface. Summary of the Invention

[0003] The main objective of this invention is to provide a method for fabricating a semiconductor structure to solve the problem of chloride ions at the junction of silicon and germanium layers affecting interface reliability in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for fabricating a semiconductor structure is provided, comprising: providing a substrate; forming a first electrode layer on a surface of one side of the substrate; forming a dielectric layer on a surface of the first electrode layer away from the substrate; forming a second electrode layer on a surface of the dielectric layer away from the first electrode layer; performing a dechlorination pretreatment on the second electrode layer; and forming a third electrode layer on a surface of the second electrode layer away from the dielectric layer.

[0005] Optionally, the second electrode layer is subjected to a dechlorination pretreatment, which includes: introducing a first boron precursor and a first germanium precursor into the surface of the second electrode layer.

[0006] Optionally, a third electrode layer is formed on the surface of the second electrode layer away from the dielectric layer, including: introducing a second boron precursor, a second germanium precursor, and a silicon precursor into the surface of the second electrode layer.

[0007] Optionally, the first boron precursor and the second boron precursor are independently selected from at least one of diborane, deuterated diborane, and boron trichloride.

[0008] Optionally, the first germanium precursor and the second germanium precursor are independently selected from at least one of germanane, digermanane, trigermanane, and germanium-based silane.

[0009] Optionally, the silicon precursor includes at least one of silane, disilane, propane, tetrasilane, and pentasilane.

[0010] Optionally, the material of the first boron precursor is the same as the material of the second boron precursor.

[0011] Optionally, the material of the first germanium precursor is the same as the material of the second germanium precursor.

[0012] Optionally, the material of the second electrode layer includes titanium nitride, and the material of the third electrode layer includes silicon germanium.

[0013] Optionally, the method further includes: providing at least one contact plug between the substrate and the first electrode layer, wherein one end of the contact plug is in direct contact with the first electrode layer and the other end is in direct contact with the substrate.

[0014] The present invention provides a method for fabricating a semiconductor structure. First, a substrate is provided; then, a first electrode layer is formed on one side of the substrate; next, a dielectric layer is formed on the surface of the first electrode layer away from the substrate; then, a second electrode layer is formed on the surface of the dielectric layer away from the first electrode layer; the second electrode layer undergoes a dechlorination pretreatment; finally, a third electrode layer is formed on the surface of the second electrode layer away from the dielectric layer. By performing the dechlorination pretreatment on the second electrode layer, chloride ions at the interface of the second electrode layer can be removed, thereby improving the reliability of the interface. Attached Figure Description

[0015] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 A schematic flowchart of a semiconductor fabrication method according to an embodiment of this application is shown;

[0017] Figures 2 to 10 A schematic diagram of a method for fabricating a semiconductor structure according to an embodiment of this application is shown.

[0018] The above figures include the following reference numerals:

[0019] 100. Substrate; 101. First electrode layer; 102. Dielectric layer; 103. Second electrode layer; 104. Third electrode layer; 105. Contact plug; 106. First support layer; 107. First sacrificial layer; 108. Second support layer; 109. Second sacrificial layer; 110. Third support layer; 111. Groove; 112. First support portion; 113. Second support portion; 114. Metal layer. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] As described in the background section, impurities can be generated at the junction of silicon and germanium layers during the fabrication of semiconductor devices in the prior art, thereby affecting the reliability of the semiconductor device interface. In order to solve the above problem, a typical embodiment of this application provides a method for fabricating a semiconductor structure.

[0024] According to embodiments of this application, a method for fabricating a semiconductor structure is provided. Figure 1 This is a flowchart of a semiconductor fabrication method according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0025] Step S201, provide a substrate;

[0026] For details, please refer to Figure 2A first support layer 106, a first sacrificial layer 107, a second support layer 108, a second sacrificial layer 109, and a third support layer 110 are sequentially stacked on a substrate 100. The first support layer 106, in addition to providing support, can also serve as an etching barrier layer. The material of the first support layer 106 can include a material with etching selectivity relative to the first sacrificial layer 107, such as silicon nitride. The materials of the first sacrificial layer 107 and the second sacrificial layer 109 can include silicon oxide, and the materials of the first sacrificial layer 107 and the second sacrificial layer 109 can be the same or different. The material of the second support layer 108 can include a material with etching selectivity relative to the first sacrificial layer 107. Similarly, the material of the third support layer 110 can also include a material with etching selectivity relative to the second sacrificial layer 109, such as silicon nitride and silicon carbonitride. The thickness of the third support layer 110 can be greater than the thickness of the second support layer 108. Then, by etching, portions of the third support layer 110, the second sacrificial layer 109, the second support layer 108, the first sacrificial layer 107, and the first support layer 106 are sequentially removed to form multiple grooves 111, thereby exposing one side of the substrate 100 to obtain a result as shown below. Figure 3 The structure shown.

[0027] In step S202, a first electrode layer 101 is formed on one side of the substrate 100, resulting in the following: Figure 4 The structure shown;

[0028] Specifically, in the actual manufacturing process, the first electrode layer 101 can be formed in multiple grooves 111. The deposition of the first electrode layer 101 can be achieved using methods such as Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD), followed by planarization through Chemical Mechanical Polishing (CMP) or Etch Back Process (EBP). The material of the first electrode layer 101 can include at least one of metallic materials, metal oxide materials, and metal nitride materials, such as titanium, titanium nitride, and iridium oxide. Furthermore, this application does not limit the shape of the first electrode layer 101; it can be as follows: Figure 4 The cylindrical or layered shape shown can have a hollow or solid internal structure.

[0029] After forming the first electrode layer 101, the steps further include forming a first support portion 112 and a second support portion 113. The first support portion 112 can be obtained by removing a portion of the third support layer 110, and similarly, the second support portion 113 can be obtained by removing a portion of the second support layer 108. Specifically, removing a portion of the third support layer 110 forms a groove 111, and the remaining third support layer 110 forms the first support portion 112, resulting in... Figure 5 The structure is shown. The first support portion 112 can be located between adjacent first electrode layers 101 to provide support for the adjacent first electrode layers 101. Then, the second sacrificial layer 109, part of the second support layer 108, and the first sacrificial layer 107 are removed in sequence, and the remaining second support layer 108 forms the second support portion 113, resulting in the structure shown. Figure 6 The structure is shown. The second support 113 can be located between adjacent first electrode layers 101. A wet leaching process can be used in the removal of the first sacrificial layer 107 and the second sacrificial layer 109.

[0030] Step S203: A dielectric layer 102 is formed on the surface of the first electrode layer 101 away from the substrate 100, resulting in... Figure 7 The structure shown;

[0031] Specifically, the dielectric layer 102 can cover the surfaces of the first support portion 112, the first electrode layer 101, and the second support portion 113. This application does not impose specific limitations on the material and internal structure of the dielectric layer 102; the material of the dielectric layer 102 only needs to meet the requirement of high dielectric constant, such as high-k materials like zirconium oxide, titanium oxide, tantalum oxide, and titanium oxide. The dielectric layer 102 can be a single-layer structure or a multi-layer composite structure. Furthermore, the dielectric layer 102 can be deposited using methods such as CVD or ALD.

[0032] Step S204: A second electrode layer 103 is formed on the surface of the dielectric layer 102 away from the first electrode layer 101, resulting in... Figure 8 The structure shown;

[0033] Specifically, the second electrode layer 103 is formed on the surface of the first electrode layer 101. The material of the second electrode layer 103 may include at least one of a metallic material, a metal oxide material, and a metal nitride material, such as titanium, titanium nitride, and iridium oxide. The second electrode layer 103 may be made of the same material as the first electrode layer 101, or it may be made of a different material. In actual manufacturing processes, the second electrode layer 103 may be formed using processes such as low-pressure chemical vapor deposition (LPCVD), plasma-enhanced chemical vapor deposition (PECVD), or ALD.

[0034] Step S205: Perform dechlorination pretreatment on the second electrode layer;

[0035] Specifically, in the formation of the second electrode layer, taking titanium nitride as an example, titanium chloride is required during the formation of titanium nitride. Therefore, chloride ions will remain on the surface of the second electrode layer. This application does not limit the specific method of dechlorination pretreatment; any scheme that can remove residual chloride ions from the surface of the second electrode layer is acceptable. Examples include chemical washing, ion exchange, ultrapure water cleaning, heat treatment, light treatment, gas treatment, surfactant treatment, electrochemical treatment, supercritical fluid treatment, and nanotechnology treatment. Among these methods, using specific chemical reagents, such as alkaline solutions like sodium hydroxide, potassium hydroxide, or ammonium hydroxide, to wash the semiconductor material can react with chloride ions to generate water-soluble compounds, thereby removing chloride ions. Ion exchange resins can facilitate the exchange of chloride ions with other ions (such as hydrogen ions or sodium ions). Repeated rinsing of the semiconductor material with ultrapure water can effectively remove surface chloride ions. Heating the semiconductor material to a certain temperature... The following methods can be used to remove chloride ions: 1) By increasing the temperature, chloride ions can volatilize or undergo chemical changes, thus achieving removal; 2) By irradiating semiconductor materials with ultraviolet light, the chemical bonds of chloride ions can be broken, causing them to decompose into harmless substances; 3) By rinsing semiconductor materials with high-purity gases, such as nitrogen, argon, or hydrogen, chloride ions can be effectively removed; 4) By using surfactants, such as nonionic or cationic surfactants, the adsorption capacity of chloride ions on the surface of semiconductor materials can be reduced, thus achieving removal; 5) By applying an electric field, the migration of chloride ions in semiconductor materials can be promoted, causing them to detach from the material surface; 6) By treating semiconductor materials with supercritical fluids, such as supercritical carbon dioxide, chloride ions can be effectively removed; 7) By utilizing nanotechnology, such as nanoparticles or nanofilms, chloride ions on the surface of the second electrode layer can be removed.

[0036] In step S206, a third electrode layer 104 is formed on the surface of the second electrode layer 103 away from the dielectric layer 102, resulting in... Figure 9 The structure shown.

[0037] Specifically, the third electrode layer 104 is formed on the surface of the second electrode layer 103. The material of the third electrode layer 104 may include a silicide material, such as silicon-germanium. In actual fabrication, the third electrode layer 104 can be formed using an LPCVD process. Furthermore, the silicide material can also be doped with p-type impurities (e.g., boron) or n-type impurities (e.g., phosphorus or arsenic) to improve the conductivity of the third electrode layer 104. Specifically, doping can be performed using either in-situ doping or non-in-situ doping processes.

[0038] In order to further accelerate the dechlorination pretreatment of the second electrode layer 103, in the embodiments of this application, step S205 can be achieved by the following steps: Step S2051: Introduce the first boron precursor and the first germanium precursor into the surface of the second electrode layer 103.

[0039] Specifically, the boron precursor and germanium precursor are chemical substances used in the chemical vapor deposition process and can be used for the thin film growth of semiconductor materials. The boron precursor and germanium precursor can be gaseous or volatile compounds that can decompose at higher temperatures to generate the desired elements or compounds. The first boron precursor can be diborane, deuterated diborane, or boron trichloride, etc. The first germanium precursor includes germanane, digerane, trigerane, and germanium-based silane, etc. In this embodiment, diborane is preferred as the first boron precursor, and germanane is preferred as the first germanium precursor. Diborane decomposes to produce hydrogen and boron, and germanane decomposes to produce hydrogen and germanium. The hydrogen produced by the decomposition of diborane and germanane can both react with chloride ions to generate hydrogen chloride gas, which is then discharged. The remaining boron and germanium are partially the same as those in the second boron precursor and second germanium precursor used in the next step (S206), therefore, no new pollution is introduced.

[0040] Specifically, step S206 includes: Step S2061: Introducing a second boron precursor, a second germanium precursor, and a silicon precursor onto the surface of the second electrode layer. This method, through the introduction of the second boron precursor, the second germanium precursor, and the silicon precursor, can further and rapidly form the third electrode layer. Specifically, the second boron precursor can be made of the same material as the first boron precursor. The second germanium precursor can also be made of the same material as the first germanium precursor. In this embodiment, since the first boron precursor and the second boron precursor are made of the same material, the need for different materials can be reduced, and the semiconductor manufacturing process can be simplified, thereby further reducing production costs and improving production efficiency.

[0041] To further improve the performance and quality of the second and third electrode layers, the material of the second electrode layer includes titanium nitride, and the material of the third electrode layer includes silicon germanium.

[0042] In another specific embodiment, the method further includes: step S207, providing at least one contact plug 105 between the substrate 100 and the first electrode layer 101, wherein one end of the contact plug 105 is in direct contact with the first electrode layer 101, and the other end is in direct contact with the substrate 100, to obtain... Figure 9 The structure shown.

[0043] In another embodiment, the step further includes forming a metal layer 114 on the surface of the third electrode layer 104 away from the second electrode layer 103, to obtain... Figure 10 The structure shown.

[0044] Specifically, the metal layer 114 is formed on the surface of the third electrode layer 104. The material of the metal layer 114 can include at least one of a metallic material, a metal oxide material, and a metal nitride material, such as tungsten, tungsten nitride, and iridium oxide. The metal layer 114 can be made of the same material as the second electrode layer 103 and the first electrode layer 101, or it can be made of a different material. In actual manufacturing processes, processes such as LPCVD, PECVD, or ALD can be used to form the metal layer 114. This application does not specifically limit the thickness of the metal layer 114. In practical applications, the thicknesses of the second electrode layer 103, the third electrode layer 104, and the metal layer 114 can be the same or different. To further reduce the resistance of the second electrode layer 103 and the metal layer 114 formed of metallic materials, the thickness of the second electrode layer 103 and the metal layer 114 can be increased in actual manufacturing processes, so that the thickness of the second electrode layer 103 and the metal layer 114 is greater than the thickness of the third electrode layer 104.

[0045] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0046] The method for fabricating a semiconductor structure according to this application involves: first, providing a substrate; then, forming a first electrode layer on one side of the substrate; next, forming a dielectric layer on the surface of the first electrode layer away from the substrate; then, forming a second electrode layer on the surface of the dielectric layer away from the first electrode layer; performing a dechlorination pretreatment on the second electrode layer; and finally, forming a third electrode layer on the surface of the second electrode layer away from the dielectric layer. By performing a dechlorination pretreatment on the second electrode layer, chloride ions at the interface of the second electrode layer can be removed, thereby improving the reliability of the interface.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a semiconductor structure, characterized in that, include: Provide substrate; A first electrode layer is formed on one side of the substrate; A dielectric layer is formed on the surface of the first electrode layer on the side away from the substrate; A second electrode layer is formed on the surface of the dielectric layer on the side away from the first electrode layer; The second electrode layer is subjected to a dechlorination pretreatment, which includes: introducing a first boron precursor and a first germanium precursor into the surface of the second electrode layer, wherein the first boron precursor is independently selected from at least one of diborane, deuterated diborane and boron trichloride, and the first germanium precursor is independently selected from at least one of germanane, digerane, trigerane and germanium-based silane. A third electrode layer is formed on the surface of the second electrode layer on the side away from the dielectric layer. Forming the first electrode layer on the surface of one side of the substrate includes: A first support layer, a first sacrificial layer, a second support layer, a second sacrificial layer, and a third support layer are sequentially stacked on the substrate. The third support layer, the second sacrificial layer, the second support layer, the first sacrificial layer, and the first support layer are removed in sequence to form multiple grooves, thereby exposing one side of the substrate. The first electrode layer is formed in the plurality of grooves, wherein the first electrode layer fills the plurality of grooves; The method further includes: At least one contact plug is provided between the substrate and the first electrode layer, wherein one end of the contact plug is in direct contact with the first electrode layer and the other end is in direct contact with the substrate.

2. The manufacturing method according to claim 1, characterized in that, A third electrode layer is formed on the surface of the second electrode layer on the side away from the dielectric layer, comprising: A second boron precursor, a second germanium precursor, and a silicon precursor are introduced into the surface of the second electrode layer.

3. The manufacturing method according to claim 2, characterized in that, The second boron precursor is selected from at least one of diborane, deuterated diborane, and boron trichloride.

4. The manufacturing method according to claim 2, characterized in that, The second germanium precursor is selected from at least one of germanane, digermanane, trigermanane, and germanylsilane.

5. The manufacturing method according to claim 2, characterized in that, The silicon precursor includes at least one of silane, disilane, propane, tetrasilane, and pentasilane.

6. The manufacturing method according to claim 2, characterized in that, The material of the first boron precursor is the same as that of the second boron precursor.

7. The manufacturing method according to claim 2, characterized in that, The material of the first germanium precursor is the same as that of the second germanium precursor.

8. The manufacturing method according to claim 2, characterized in that, The material of the second electrode layer includes titanium nitride, and the material of the third electrode layer includes silicon germanium.

9. A method for fabricating a semiconductor structure, characterized in that, include: Provide substrate; A first electrode layer is formed on one side of the substrate; A dielectric layer is formed on the surface of the first electrode layer on the side away from the substrate; A second electrode layer is formed on the surface of the dielectric layer on the side away from the first electrode layer; First, the second electrode layer is pretreated to remove chlorine, specifically by introducing diborane and germanane into the surface of the second electrode layer; Then, a third electrode layer is formed on the surface of the second electrode layer away from the dielectric layer, specifically by introducing diborane, germanane, and silicon precursor into the surface of the second electrode layer.

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