Semiconductor film doping method and semiconductor structure

Abstract

The invention provides a semiconductor film doping method, which comprises the steps of providing a semiconductor substrate doped with a target element, and the doping concentration of the target element is greater than 1; the semiconductor substrate is heated to a first temperature, a target film layer is deposited on the semiconductor substrate, in the deposition process, the target element is diffused into the target film layer, a target doped film layer is obtained, and the first temperature is higher than the activation temperature of the target element in the solid state diffusion process. The invention further provides another semiconductor film layer doping method, which is different from the method, the target film layer is formed on the semiconductor substrate through deposition, then annealing treatment is carried out on the semiconductor substrate at a second temperature, so that the target element in the semiconductor substrate is diffused into the target film layer, and a target doped film layer is obtained, the second temperature is higher than the activation temperature of the target element in the solid-state diffusion process. The invention also provides a semiconductor structure prepared by using the method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor material preparation, and more particularly, to a semiconductor film layer doping method and a semiconductor structure. BACKGROUND

[0002] Element doping of a semiconductor film layer is a core means for regulating the electrical and optical properties of a material, and is also a basic process for manufacturing various electronic and optoelectronic devices. The type, concentration and distribution uniformity of the doping element directly determine the core performance and reliability of the device.

[0003] In the prior art, methods for realizing semiconductor film layer doping mainly include: 1. Ion implantation, in which high-energy particle beams are used to implant doping ions into the lattice of the film layer; 2. In-situ doping, such as metal organic chemical vapor deposition and molecular beam epitaxy, in which a doping source is introduced simultaneously during film layer growth; and 3. Co-deposition, such as sputter deposition using a composite target material composed of a doping element and a base element to realize simultaneous doping and film formation.

[0004] However, ion implantation requires expensive equipment and has high operating and maintenance costs. In addition, the high-energy ion implantation process can cause serious damage to the lattice structure of the semiconductor film layer, resulting in a decrease in the crystalline quality of the film layer, which must rely on a subsequent high-temperature annealing process for lattice repair. However, the high-temperature annealing process can easily cause material components to volatilize, separate or damage the device structure, limiting its application in heat-sensitive material systems. In the case of low-concentration doping, co-deposition has difficulty in accurately controlling the distribution uniformity of the doping element in the film layer, and the preparation process of the composite target material is difficult, as the target material for a specific doping ratio needs to be custom-made. The in-situ growth doping method has a complex process, harsh reaction conditions, high equipment investment and high process costs, which is not conducive to large-scale production and application. SUMMARY

[0005] In view of the above problems, the present application provides a semiconductor film layer doping method capable of obtaining high-quality semiconductor doped film layers and significantly reducing manufacturing costs, as well as a semiconductor structure obtained by the method.

[0006] According to a first aspect of the present application, a semiconductor film layer doping method is provided, comprising: providing a semiconductor substrate doped with a target element, the doping concentration of the target element being greater than 1 ; heating the semiconductor substrate to a first temperature and depositing a target film layer on the semiconductor substrate, during the deposition process, the target element diffuses into the target film layer to obtain a target doped film layer, wherein the first temperature is greater than the activation temperature of the target element in the solid-state diffusion process.

[0007] According to a second aspect of this application, a semiconductor film doping method is provided, comprising: providing a semiconductor substrate, wherein the semiconductor substrate is doped with a target element, the doping concentration of the target element being greater than 1. A target film layer is deposited on a semiconductor substrate; the semiconductor substrate is annealed at a second temperature to allow the target element in the semiconductor substrate to diffuse into the target film layer, thereby obtaining the target doped film layer, wherein the second temperature is greater than the activation temperature of the target element during solid-state diffusion.

[0008] According to an embodiment of this application, the target element is a V-family element.

[0009] According to embodiments of this application, the target film layer is made of a II-VI group material.

[0010] According to embodiments of this application, a target element is doped in a semiconductor substrate using a vacuum deposition method.

[0011] According to an embodiment of this application, after depositing the target film layer on the semiconductor substrate, the method further includes annealing the semiconductor substrate at a first temperature.

[0012] According to an embodiment of this application, the first temperature is between 200°C and 800°C.

[0013] According to embodiments of this application, a target film layer is deposited on a semiconductor substrate using a vacuum deposition method.

[0014] According to an embodiment of this application, the second temperature is between 200°C and 800°C.

[0015] According to an embodiment of this application, a semiconductor substrate is heated to a third temperature, and a target film layer is deposited on the semiconductor substrate using atomic layer deposition, wherein the third temperature is lower than the second temperature.

[0016] According to a third aspect of this application, a semiconductor structure is provided, which is prepared by the semiconductor film doping method described in any of the preceding claims, wherein the target element exhibits a concentration gradient distribution or a uniform distribution from the semiconductor substrate to the target film layer.

[0017] The above one or more embodiments have the following beneficial effects:

[0018] This application pre-dops the target element into the semiconductor substrate, combining the deposition of the target film layer with the target film layer doping step into one, significantly simplifying the process and reducing manufacturing costs. This application uses a thermal diffusion mechanism instead of high-energy particle bombardment, fundamentally avoiding lattice damage caused by ion implantation. In addition, the annealing process can repair semiconductor losses and promote the secondary growth of semiconductor grains, thereby obtaining a higher quality target-doped film layer. Furthermore, the film layer doping method provided by this application is compatible with mature industrial deposition production technologies such as magnetron sputtering and thermal evaporation, without requiring large-scale equipment modifications to existing industrial production lines, greatly reducing manufacturing costs. At the same time, it can leverage the high mass production capacity, stable process window, and precise film thickness control advantages of these mature technologies to achieve efficient mass production of target-doped films. Attached Figure Description

[0019] The above-mentioned contents, other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A flowchart illustrating a semiconductor film doping method according to an embodiment of this application is shown schematically.

[0021] Figure 2 A flowchart illustrating a semiconductor film doping method according to another embodiment of this application is shown schematically;

[0022] Figure 3 This illustration shows a schematic diagram of depositing a target film on a semiconductor substrate using magnetron sputtering according to an embodiment of this application.

[0023] It should be noted that, for clarity, the dimensions of the overall / partial structure or the overall / partial region in the drawings used to describe the embodiments of this application may be enlarged or reduced, that is, these drawings are not drawn to actual scale.

[0024] Component designation explanation

[0025] 1 substrate 2 target material 3 target film layer Detailed Implementation

[0026] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0029] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0030] In related technologies, elemental doping methods for semiconductor films mainly include ion implantation, in-situ doping, and co-deposition. However, these methods suffer from high equipment maintenance costs, easy damage to the film lattice, limitations on the application of thermosensitive materials, complex processes, harsh reaction conditions, and high costs. Therefore, there is an urgent need to develop a new semiconductor film doping technology that is low-cost, has low lattice damage, is simple to process, and is compatible with thermosensitive material systems. This would address the bottlenecks of existing methods in terms of equipment cost, film quality, application scenario adaptability, and large-scale production, providing more efficient process support for the fabrication of high-performance electronic and optoelectronic devices.

[0031] Figure 1 A flowchart illustrating a semiconductor film doping method according to an embodiment of this application is shown.

[0032] like Figure 1 As shown, the semiconductor film doping method of this embodiment includes operations S110 to S120.

[0033] In operation S110, a semiconductor substrate is provided, in which a target element is doped, and the doping concentration of the target element is greater than 1. .

[0034] According to an embodiment of this application, a semiconductor substrate is first provided, and then a target element is doped into the semiconductor substrate using a vacuum deposition method to obtain a semiconductor substrate doped with the target element. In this embodiment, plasma-enhanced chemical vapor deposition (PECVD) is used to dope the semiconductor substrate with the target element. Specifically, the substrate is first pretreated, such as by ultrasonic cleaning, to remove oil and particulate impurities from the surface of the semiconductor substrate; the pretreated substrate is then fixed on the PECVD reaction chamber base and evacuated to a vacuum level. - Pa is used to eliminate air impurities and introduce a carrier gas (such as argon or nitrogen) and a precursor gas containing the target dopant element, controlling the gas flow ratio and chamber pressure. A radio frequency electric field is applied to ionize the gas in the reaction chamber to form plasma, which activates the dopant element atoms in the precursor. The dopant atoms in the plasma undergo a chemical reaction on the substrate surface, bond with the substrate atoms, and deposit to form a doped layer. After the reaction is completed, the gas supply is stopped and the chamber is cooled. After the temperature drops to room temperature, the sample is taken out to obtain a semiconductor substrate doped with the target element.

[0035] According to embodiments of this application, the doping concentration of the target element is greater than 1. The target element forms a significant concentration gradient in the substrate. This gradient provides sufficient impetus for the diffusion of the target element, thereby driving a sufficient amount of target element to continuously migrate from the substrate to the newly deposited target film, ultimately enabling the doping concentration of the target film to accurately meet the preset requirements.

[0036] According to embodiments of this application, the target element is a Group V element, such as: 1. Phosphorus, the most commonly used Group V doping element, suitable for mainstream semiconductor substrates such as silicon and germanium, with good doping uniformity and controllable diffusion, making it the first choice for heavy doping of silicon-based devices; 2. Arsenic, commonly used for shallow junction doping of high-voltage devices or very large-scale integrated circuits; 3. Antimony, suitable for deep-level doping or power devices requiring long-term stability, and can also be co-doped with phosphorus to optimize carrier distribution; 4. Bismuth, a special Group V doping element used in compound semiconductors (such as gallium arsenide and silicon carbide), which can adjust the bandgap structure and improve the high-temperature stability of devices. In other optional embodiments, the target element can also be other elements, such as Group V or Group III doping elements, which are not limited here.

[0037] In this embodiment, the semiconductor substrate is a silicon substrate, which is doped with the target element phosphorus, and the phosphorus atom concentration in the substrate is approximately 5. .

[0038] In operation S120, the semiconductor substrate is heated to a first temperature, and a target film layer is deposited on the semiconductor substrate. During the deposition process, the target element diffuses into the target film layer to obtain a target doped film layer. The first temperature is greater than the activation temperature of the target element during solid-state diffusion.

[0039] According to an embodiment of this application, a semiconductor substrate doped with a target element is heated to a first temperature higher than the solid-state diffusion activation temperature of the target element, and a target film layer is deposited at the first temperature. During the deposition process, the target element in the substrate continues to diffuse into the target film layer with the help of high temperature, thereby simultaneously achieving film layer growth and uniform doping, and finally obtaining a target doped film layer doped with the target element.

[0040] According to an embodiment of this application, the first temperature is between 200°C and 800°C. At this temperature, the target element in the substrate can break through the lattice constraint and generate migration power by means of the concentration gradient, while avoiding substrate lattice damage or film interface degradation caused by high temperature. At the same time, the target film is in a loose growth stage, which can reduce the element diffusion resistance and allow the target element to penetrate uniformly and synchronously with the formation of the target film. Finally, the target doped film is obtained under the premise of ensuring the film density and substrate adhesion.

[0041] According to embodiments of this application, the target film is made of a group II-VI material, such as a group II-VI semiconductor material. Group II-VI semiconductor materials are composed of group II metallic elements (such as Zn, Cd, Hg) and group VI non-metallic elements (such as O, S, Se, Te), for example, ZnS, CdSe, ZnO, CdTe, and CdS. In other optional embodiments, the target film can also be other semiconductor materials, such as group III-V semiconductor materials; it can also be a group II-VI alloy material, such as CdSeTe, CdMgTe, CdZnTe, CdSTe, CdMgSTe, ZnCdMgSeTe, etc., without limitation.

[0042] In this embodiment, a target film layer is deposited on a semiconductor substrate using magnetron sputtering. Specifically, as shown... Figure 3 As shown, substrate 1 was placed in a magnetron sputtering chamber and heated to 300°C. Under a working gas atmosphere (high-purity argon, 2 Pa), high-purity zinc telluride (ZnTe) target material 2 was bombarded using radio frequency magnetron sputtering to deposit a ZnTe target film 3 on the substrate. During the deposition process, substrate 1 was maintained at approximately 300°C, which provided sufficient thermal activation energy for phosphorus to escape from the substrate and diffuse into the ZnTe target film 3 via solid-state diffusion. After deposition, heating was turned off, and the sample was cooled in argon gas.

[0043] In one optional embodiment, after depositing the target film on the semiconductor substrate, the semiconductor substrate is further subjected to an annealing treatment at a first temperature. The annealing treatment can promote the uniform diffusion and activation of the target element, improve the carrier mobility, enhance the doping effect of the target element, and repair lattice defects generated during the deposition process, thereby improving the crystal quality of the film.

[0044] This application also provides a semiconductor structure prepared by the above-described semiconductor film doping method, in which the target element exhibits a concentration gradient distribution from the semiconductor substrate to the target film layer. Energy dispersive X-ray spectroscopy (EDS) was performed on this semiconductor structure, and the results show that the target element clearly diffuses from the semiconductor substrate into the target film layer. Figure 3 As shown, a highly concentrated doped region is formed at the interface between the substrate 1 and the target film 3, extending from the side of the target film 3 facing the substrate 1 to the side away from the substrate 1. Figure 3 As shown in the bottom-up direction, the doping concentration gradually decreases.

[0045] In another optional embodiment, in the semiconductor structure prepared by the above-described semiconductor film doping method, the target element is uniformly distributed from the semiconductor substrate to the target film layer. That is, from the interface between the semiconductor substrate and the target film layer to the outer surface of the target film layer, the concentration of the target element exhibits a continuous and uniform distribution along the entire longitudinal thickness direction, without any local concentration abrupt changes, enrichment, or depletion.

[0046] This application pre-dops the target element into the semiconductor substrate, combining the deposition of the target film layer with the target film layer doping step into one, significantly simplifying the process flow and reducing manufacturing costs. This application uses a thermal diffusion mechanism instead of high-energy particle bombardment, fundamentally avoiding lattice damage caused by ion implantation. In addition, the annealing process can repair semiconductor losses and promote the secondary growth of semiconductor grains, thereby obtaining a higher quality target-doped film layer. Furthermore, the film layer doping method provided by this application is compatible with mature industrial deposition technologies such as magnetron sputtering, thermal evaporation, vapor transport deposition, and near-space sublimation, without requiring large-scale equipment modifications to existing industrial production lines, greatly reducing manufacturing costs. At the same time, it can leverage the high mass production capacity, stable process window, and precise film thickness control advantages of these mature technologies to achieve efficient mass production of target-doped films.

[0047] Figure 2 A flowchart illustrating a semiconductor film doping method according to another embodiment of this application is shown schematically.

[0048] like Figure 2As shown, the semiconductor film doping method of this embodiment includes operations S210 to S230.

[0049] In operation S210, a semiconductor substrate is provided, in which a target element is doped, and the doping concentration of the target element is greater than 1. .

[0050] According to an embodiment of this application, a semiconductor substrate is first provided, and then a target element is doped into the semiconductor substrate using a vacuum deposition method to obtain a semiconductor substrate doped with the target element. In this embodiment, plasma-enhanced chemical vapor deposition (PECVD) is used to dope the semiconductor substrate with the target element. Specifically, the substrate is first pretreated, such as by ultrasonic cleaning, to remove oil and particulate impurities from the surface of the semiconductor substrate; the pretreated substrate is then fixed on the PECVD reaction chamber base and evacuated to a vacuum level. - Pa is used to eliminate air impurities and introduce a carrier gas (such as argon or nitrogen) and a precursor gas containing the target dopant element, controlling the gas flow ratio and chamber pressure. A radio frequency electric field is applied to ionize the gas in the reaction chamber to form plasma, which activates the dopant element atoms in the precursor. The dopant atoms in the plasma undergo a chemical reaction on the substrate surface, bond with the substrate atoms, and deposit to form a doped layer. After the reaction is completed, the gas supply is stopped and the chamber is cooled. After the temperature drops to room temperature, the sample is taken out to obtain a semiconductor substrate doped with the target element.

[0051] According to embodiments of this application, the doping concentration of the target element is greater than 1. The target element forms a significant concentration gradient in the substrate. This gradient provides sufficient impetus for the diffusion of the target element, thereby driving a sufficient amount of target element to continuously migrate from the substrate to the newly deposited target film, ultimately enabling the doping concentration of the target film to accurately meet the preset requirements.

[0052] According to embodiments of this application, the target element is a Group V element, such as nitrogen, phosphorus, arsenic, antimony, or bismuth. In other optional embodiments, the target element may also be other elements, such as Group V or Group III dopants, and this is not limited here. In this embodiment, the semiconductor substrate is a silicon substrate, in which nitrogen, the target element, is doped.

[0053] In operation S220, the target film layer is deposited on the semiconductor substrate.

[0054] According to an embodiment of this application, a semiconductor substrate is heated to a third temperature to deposit and form a target film layer on the semiconductor substrate. The third temperature is lower than the second temperature, which is higher than the activation temperature of the target element during solid-state diffusion. In other words, the third temperature is low, and the target element will not undergo solid-state diffusion at the third temperature.

[0055] According to embodiments of this application, the target film is made of a group II-VI material, such as a group II-VI semiconductor material, which is composed of group II metal elements (such as Zn, Cd, Hg) and group VI non-metal elements (such as O, S, Se, Te). In other alternative embodiments, the target film may also be other semiconductor materials, such as group III-V semiconductor materials, or group II-VI alloy materials; no limitation is imposed here.

[0056] In this embodiment, a ZnTe target film is deposited on a semiconductor substrate at 200°C using atomic layer deposition (ALD). Specifically, a Zn source precursor is first introduced into the reaction chamber, where it undergoes chemisorption on the substrate surface and forms a monolayer. Then, an inert gas is introduced to purge the chamber, removing unreacted Zn source precursor and any potential byproducts. Next, a Te source precursor is introduced, which reacts with the zinc species adsorbed on the substrate surface to generate ZnTe thin film units. The chamber is then purged again with an inert gas to complete a single ALD cycle. This cycle is repeated until a ZnTe film of the target thickness is obtained.

[0057] In operation S230, the semiconductor substrate is annealed at a second temperature to allow the target element in the semiconductor substrate to diffuse into the target film layer, thereby obtaining the target doped film layer. The second temperature is greater than the activation temperature of the target element during solid-state diffusion.

[0058] According to an embodiment of this application, the second temperature is between 200°C and 800°C. At this temperature, the target element in the substrate can break through the lattice constraint and generate migration power by means of the concentration gradient, thereby obtaining the target doped film layer. Specifically, after deposition, the sample is transferred into a rapid thermal processing device and annealed under a nitrogen atmosphere, for example, at 300°C for 60 minutes. During the annealing process, the target element diffuses from the semiconductor substrate into the ZnTe target film layer, thereby obtaining the target doped film layer.

[0059] This application also provides a semiconductor structure prepared by the above-described semiconductor film doping method, wherein the target element exhibits a concentration gradient distribution from the semiconductor substrate to the target film layer. That is, in this semiconductor structure, a doped region with a high concentration can be formed at the interface between the semiconductor substrate and the target film layer, and the doping concentration gradually decreases from the side of the target film layer facing the semiconductor substrate to the side away from the semiconductor substrate.

[0060] In another optional embodiment, in the semiconductor structure prepared by the above-described semiconductor film doping method, the target element is uniformly distributed from the semiconductor substrate to the target film layer. That is, from the interface between the semiconductor substrate and the target film layer to the outer surface of the target film layer, the concentration of the target element exhibits a continuous and uniform distribution along the entire longitudinal thickness direction, without any local concentration abrupt changes, enrichment, or depletion.

[0061] This application employs a thermal diffusion mechanism rather than high-energy particle bombardment, fundamentally avoiding lattice damage caused by ion implantation. Furthermore, the annealing process can repair semiconductor losses and promote secondary growth of semiconductor grains, thereby obtaining a higher quality target doped film. In addition, the film doping method provided in this application is compatible with mature industrial deposition production technologies, eliminating the need for large-scale equipment modifications to existing industrial production lines, significantly reducing manufacturing costs. At the same time, it can leverage the high production capacity, stable process window, and precise film thickness control advantages of these mature technologies to achieve efficient mass production of target doped films.

[0062] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. A method for doping a semiconductor film, characterized in that, include: A semiconductor substrate is provided, wherein the semiconductor substrate is doped with a target element, and the doping concentration of the target element is greater than 1. ; The semiconductor substrate is heated to a first temperature, and a target film is deposited on the semiconductor substrate. During the deposition process, the target element diffuses into the target film to obtain a target doped film. The first temperature is greater than the activation temperature of the target element during solid-state diffusion.

2. A method for doping a semiconductor film, characterized in that, include: A semiconductor substrate is provided, wherein the semiconductor substrate is doped with a target element, and the doping concentration of the target element is greater than 1. ; The target film layer is deposited on the semiconductor substrate; The semiconductor substrate is annealed at a second temperature to allow the target element in the semiconductor substrate to diffuse into the target film layer, thereby obtaining a target doped film layer, wherein the second temperature is greater than the activation temperature of the target element during solid-state diffusion.

3. The semiconductor film doping method according to claim 1 or 2, characterized in that, The target element is a V-family element.

4. The semiconductor film doping method according to claim 1 or 2, characterized in that, The target membrane is made of a II-VI group material.

5. The semiconductor film doping method according to claim 1 or 2, characterized in that, The target element is doped in the semiconductor substrate using a vacuum deposition method.

6. The semiconductor film doping method according to claim 1, characterized in that, After depositing the target film on the semiconductor substrate, the process further includes annealing the semiconductor substrate at the first temperature.

7. The semiconductor film doping method according to claim 6, characterized in that, The first temperature is between 200℃ and 800℃.

8. The semiconductor film doping method according to claim 1, characterized in that, The target film layer is deposited on the semiconductor substrate using vacuum deposition.

9. The semiconductor film doping method according to claim 2, characterized in that, The second temperature is between 200℃ and 800℃.

10. The semiconductor film doping method according to claim 2, characterized in that, The semiconductor substrate is heated to a third temperature, and a target film layer is deposited on the semiconductor substrate using a vacuum deposition method. The third temperature is lower than the second temperature.

11. A semiconductor structure, characterized in that, The semiconductor structure is prepared by the semiconductor film doping method according to any one of claims 1 to 10, wherein the target element exhibits a concentration gradient distribution or a uniform distribution from the semiconductor substrate to the target film.

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