Preparation of P-type impurity source and doping technique

Abstract

First, liquid gallium aluminum nitrate is coated on N type silicon chip. Then, the coated chip is put into diffusion furnace in open pipe system adopted. Under protection of nitrogen atmosphere, P type diffusion is completed through one time of continuous high temperature. Solid gallium aluminum nitrate is generated in reaction vessel through reaction among 0.8-1.5 portion (weight) of gallium in high purity or gallium oxide, 0.5-l portion of aluminum powder in high purity or aluminum oxide and nitric acid. Liquid gallium aluminum nitrate is obtained by dissolving solid gallium aluminum nitrate in absolute ethyl alcohol. Features are: simple technique, easy of operation, even diffusion and better repeatability, better distributed impurity concentration, low cost. Qualification rate is increased to 5-10%.

Description

Technical field: [0001] The invention belongs to the preparation and doping process of a P-type impurity source in the production of power semiconductor devices. Background technique: [0002] At present, the one-time P-type doping process in the thyristor production process mainly includes closed-tube aluminum-gallium diffusion and boron-aluminum coating diffusion. Influenced by the quantity and quality of quartz tubes, the diffusion parameters are not easy to adjust, the parameters are highly dispersed, the repeatability is poor, the cycle is long, and the cost is high; the boron-aluminum coating diffusion process, the impurity concentration distribution is not ideal, because the boron impurity distribution is steep, resulting in The electrical parameters are highly dispersed, and the product qualification rate and excellent product rate are low. Due to the shortcomings of the above two diffusion processes, the quality and production development of power semiconductor dev...

AI Technical Summary

Problems solved by technology

[0002] At present, the one-time P-type doping process in the thyristor production process mainly includes closed-tube aluminum-gallium diffusion and boron-aluminum coating diffusion. Influenced by the quantity and quality of quartz tubes, the diffusion parameters are not easy to adjust, the parameters are highly dispersed, the repeatability is poor, the cycle is long, and the cost is high; the boron-aluminum coating diffusion process, the impurity concentration distribution is not ideal, because the boron impurity distribution is steep, resulting in Large dispersion of electrical parameters, low product qualification rate and excellent product rate, etc.

Due to the shortcomings of the above two diffusion processes, it directly affects the quality and production development of power semiconductor devices, which in turn affects economic benefits