Boron-containing dopant slurry and application thereof

Abstract

The invention provides boron-containing dopant slurry. The boron-containing dopant slurry is prepared from the following components in parts by weight: 5-70 parts of organic borate, 15-50 parts of polyol, 10-40 parts of dihydroxy ylamine and 0.1-2.5 parts of organic quaternary ammonium salt. The invention further provides a silicon wafer boron doping method. The silicon wafer boron doping method comprises the following steps that (1) the boron-containing dopant slurry is subjected to spraying or screen printing on the surface of a silicon wafer; (2) the silicon wafer treated in the step (1) isplaced into a diffusion furnace for boron diffusion, wherein the diffusion temperature is 700-850 DEG C. The boron-containing dopant slurry can realize low-temperature boron doping, thermal energy consumption can be obviously reduced, and damage to a crystal structure and electrical performance of a crystalline silicon substrate is reduced.

Description

technical field [0001] The invention relates to boron-containing dopant slurry and its application. Background technique [0002] At present, boron doping on the surface of crystalline silicon still mainly adopts vapor phase deposition and diffusion process. This method generally uses BBr 3 is the boron source, BBr 3 molecules in the diffusion furnace tube with O 2 Oxidation reaction to produce B 2 o 3 , then at high temperature B 2 o 3 It will undergo redox reaction with Si to form boron and SiO 2 , boron is diffused into crystalline silicon at high temperature, and finally forms a diffusion junction. If the crystalline silicon is p-type, a boron high-low junction is formed; if the crystalline silicon is n-type, a PN junction is formed. Almost the entire vapor deposition and diffusion process needs to be carried out in a high temperature environment above 900°C, especially in the diffusion stage, which generally requires a high temperature of 950°C to 1000°C in the...

AI Technical Summary

Problems solved by technology

However, there are two problems that cannot be avoided: one is the high cost of preparing silicon spheres, especially the nanoscale silicon spheres mentioned in the patent, which are very expensive; the other is that according to the patent, the boron doping of silicon spheres depends on silicon spheres together Boron enters the silicon substrate together to complete this process, but this process requires a higher temperature, which cannot be achieved by ordinary thermal diffusion. It must be combined with laser doping local high temperature diffusion method

Patent CN103059666A provides a coating solution for boron diffusion, which is only suitable for traditional high-temperature boron doping process

Images