Novel semiconductor doping process

Abstract

The invention discloses a novel semiconductor doping process. The novel semiconductor doping process specifically comprises the following steps: (1) plating a protective layer on a substrate; (2) doping required ions on the protective layer in an injection or uniform source mode; (3) performing high-temperature pre-diffusion, and controlling the actual concentration of ions entering the substrate by adjusting the temperature and the time; (4) stripping off the protective layer on the surface of the substrate; and (5) performing formal diffusion on the substrate to finish doping. According to the invention, the doping concentration is controlled by adding the protective layer on the basis of traditional injection and uniform source, and the doping concentration and the process are confirmed through semiconductor process simulation and a device simulation tool Silvaco TCAD, so that the doping cost and the doping uniformity can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and more specifically, to a novel semiconductor doping process. Background Art

[0002] In the process of continuous development of semiconductor chips, the requirements for equipment are becoming more and more stringent. Among them, doping diffusion, as the most important process for chips, has particularly strict equipment requirements, so the cost requirements have increased sharply.

[0003] Currently, semiconductor doping is a very important process in the semiconductor production process, which directly determines the characteristics of the P / N junction to a certain extent.

[0004] However, in the actual production process, due to equipment limitations, the required concentration is often not achieved. For example, there is no injector or the injector cannot meet the uniformity requirements at low concentrations.

[0005] Therefore, how to develop a novel semiconductor doping process is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a novel semiconductor doping process to solve the deficiencies in the prior art.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A novel semiconductor doping process specifically includes the following steps:

[0009] (1) Deposit a protective layer on the substrate;

[0010] (2) Dope the required ions on the protective layer by injection or homogenization source;

[0011] (3) Perform high-temperature pre-diffusion, and control the actual ion concentration entering the substrate by adjusting the temperature and time;

[0012] (4) Strip off the protective layer on the surface of the substrate;

[0013] (5) Perform formal diffusion on the substrate to complete doping.

[0014] Further, in the above step (1), the material of the substrate is Si, GaN, GaAs or SiC.

[0015] Further, in the above step (1), the substrate is an N-type semiconductor doped wafer or a P-type semiconductor doped wafer. Further, the doping ions of the N-type semiconductor doped wafer include phosphorus, arsenic, tellurium, and bismuth, and the doping ions of the P-type semiconductor doped wafer include boron, aluminum, gallium, indium, and thallium.

[0016] Further, in the above step (1), the material of the protective layer is SiO 2 , SiC or SiN.

[0017] Further, in the above step (3), the temperature is 1000 - 1500 °C and the time is 1 - 24 h.

[0018] Further, in the above step (3), the actual ion concentration entering the substrate is confirmed by measuring the sheet resistance or through semiconductor process simulation and device simulation tool (semiconductor process and device simulation software) Silvaco TCAD.

[0019] Further, in the above step (4), the stripping method is a wet etching process or a dry etching process.

[0020] Further, in the above step (5), the formal diffusion adjusts the gas, temperature and time according to the required junction depth of the actual concentration. Further, the above gas is nitrogen or argon, the temperature is 1000 - 1500 °C, and the time is 1 - 24 h.

[0021] From the above technical solutions, compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The present invention controls the doping concentration by adding a protective layer on the basis of traditional implantation and source homogenization, and confirms the doping concentration and process through semiconductor process simulation and device simulation tool Silvaco TCAD, which is beneficial to reducing the doping cost and doping uniformity.

[0023] 2. If an enterprise has no implantation equipment or the implantation equipment cannot reach the required implantation concentration, the thin film stripping method of the present invention can be used to solve this problem. A protective layer is plated on the substrate to be doped, and then the required ions are doped on the protective layer by implantation or source homogenization, followed by high-temperature pre-diffusion. The actual ion concentration entering the substrate is controlled by adjusting the temperature and time. Finally, the protective layer on the surface of the substrate is stripped to complete the doping in the formal diffusion.

[0024] 3. The present invention can not only solve the equipment cost problem, but also provide a possible low-concentration implantation solution when the implantation equipment reaches a bottleneck, providing experience for the next semiconductor doping technology.

[0025] 4. On the one hand, the present invention can complete low-concentration doping without an implanter, and on the other hand, it can effectively solve the problem of poor implantation uniformity of some implanters at low concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of the new semiconductor doping process in Example 1;

[0027] Figure 2 Schematic flow diagram of the novel semiconductor doping process in Example 2;

[0028] Figure 3 Simulation of the novel semiconductor doping process in Example 1;

[0029] Figure 4 Simulation data of the novel semiconductor doping process in Example 1. Detailed implementation manners

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Example 1

[0032] The novel semiconductor doping process, as Figure 1 shown, specifically includes the following steps:

[0033] (1) Using plasma enhanced chemical vapor deposition (PECVD) technology, deposit a SiO protection layer with a thickness of 0.3 μm on the N-type single crystal Si substrate; 2 Protection layer;

[0034] (2) Inject a layer of P-type boron ions on the protection layer, with an injection concentration of 2.5e18;

[0035] (3) High-temperature pre-diffusion, by adjusting the temperature to 950 - 1050 °C and the time to 1 - 12 h, control the ion concentration actually entering the N-type single crystal Si substrate;

[0036] (4) Strip the protection layer on the surface of the N-type single crystal Si substrate by hydrofluoric acid;

[0037] (5) Formal diffusion of the N-type single crystal Si substrate, adjust the gas to nitrogen according to the required junction depth of the actual concentration, the temperature to 950 - 1050 °C, and the time to 1 - 12 h to complete doping.

[0038] Example 2

[0039] The novel semiconductor doping process, as Figure 2 shown, specifically includes the following steps:

[0040] (1) Using Plasma Enhanced Chemical Vapor Deposition (PECVD) technology, a 0.3-μm-thick SiN protective layer is deposited on a P-type SiC substrate;

[0041] (2) A layer of N-type phosphorus ions is uniformly sourced on the protective layer, and the uniform source concentration is 2.5e18;

[0042] (3) High-temperature pre-diffusion, by adjusting the temperature to 950 - 1050 °C and the time to 1 - 12 h, to control the ion concentration actually entering the P-type SiC substrate;

[0043] (4) The protective layer on the surface of the P-type SiC substrate is stripped off by hydrofluoric acid;

[0044] (5) The P-type SiC substrate is formally diffused. According to the required junction depth of the actual concentration, the gas is adjusted to argon, the temperature is 950 - 1050 °C, and the time is 1 - 12 h to complete doping.

[0045] Performance testing

[0046] The novel semiconductor doping process of Example 1 is preliminarily verified in the semiconductor process simulation and device simulation tool Silvaco TCAD. The results are as Figures 3 - 4 shown.

[0047] It can be seen from Figures 3 - 4 that this simulation software can simulate relevant parameters such as the corresponding PN junction depth and doping concentration.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel semiconductor doping process, characterized in that: The specific steps include: (1) Plating a protective layer on the substrate; (2) doping the protective layer with the desired ions by injection or homogenization; (3) High-temperature pre-diffusion, which controls the actual ion concentration entering the substrate by adjusting the temperature and time; (4) peeling off the protective layer on the surface of the substrate; (5) The substrate is formally diffused and doping is completed.

2. A novel semiconductor doping process according to claim 1, characterized in that: In step (1), the material of the substrate is Si, GaN, GaAs or SiC.

3. A novel semiconductor doping process according to claim 1, characterized in that: In step (1), the substrate is an N-type semiconductor doped sheet or a P-type semiconductor doped sheet.

4. A novel semiconductor doping process according to claim 3, characterized in that: The doping ions of the N-type semiconductor doping sheet include bismuth, arsenic, phosphorus and tellurium, and the doping ions of the P-type semiconductor doping sheet include boron, aluminum, gallium, indium and thallium.

5. A novel semiconductor doping process according to claim 1, characterized in that: In step (1), the material of the protective layer is SiO2, SiC or SiN.

6. A novel semiconductor doping process according to claim 1, characterized in that: In step (3), the temperature is 1000-1500° C., and the time is 1-24 hours.

7. A novel semiconductor doping process according to claim 1, characterized in that: In step (3), the actual ion concentration entering the substrate is confirmed by testing the sheet resistance or semiconductor process simulation and device simulation tool Silvaco TCAD.

8. A novel semiconductor doping process according to claim 1, characterized in that: In step (4), the stripping method is a wet etching process or a dry etching process.

9. A novel semiconductor doping process according to claim 1, characterized in that: In step (5), the formal diffusion adjusts the gas, temperature and time according to the required junction depth of the actual concentration.

10. A novel semiconductor doping process according to claim 9, characterized in that: The gas is nitrogen or argon, the temperature is 1000-1500° C., and the time is 1-24 hours.

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