Planar continuous boron expanding method

Abstract

The invention relates to a boron expanding technique for forming a PN junction, and particularly to a planar continuous expanding method. The method comprises the steps of mixing boron-containing oxide powder or boron-containing nitride powder or mixture of the boron-containing oxide powder and the boron-containing nitride powder with alcohol solution, thereby forming spraying solution; then spraying the formed spraying solution on the surface of a silicon wafer, and forming the PN junction through diffusion after high-temperature treatment. The planar continuous boron expanding method has advantages of no silicon chip pollution, low process temperature and controllable doping density. Furthermore used continuous processing equipment does not require a temperature increase process or a temperature reduction process and realizes continuous operation. The planar continuous boron expanding method settles the problems of high boron expansion temperature, low uniformity, and incapability of realizing continuous production. The planar continuous boron expanding method has relatively high practicability and belongs to updated technology.

Description

technical field [0001] The invention relates to a boron diffusion technology for forming a PN junction, in particular to a planar continuous boron diffusion method. Background technique [0002] At present, there are more and more researches on boron diffusion technology. Among them, patent 201210259115.3 discloses a boron diffusion method for crystalline silicon solar cells, which is to form a relatively high impurity concentration in the shallow depth range of the silicon wafer surface to It is beneficial to form a good ohmic contact, thereby improving battery performance. However, this patent cannot achieve low doping concentration, that is, it cannot be used for the preparation of PN junctions. Patent 201210548232 discloses a coating solution for boron diffusion, which includes boron compound, organic binder, silicon compound, alumina precursor, and water or organic solvent, the coating solution is used to diffuse boron into silicon In order to form a P-type diffusion ...

AI Technical Summary

Problems solved by technology

[0003] To sum up, the traditional boron diffusion technology mostly adopts tubular diffusion, the temperature is high and usually one furnace is operated, and the operating cost is higher. Some boron diffusion technologies are still based on organic binder coating liquid. The process will bring pollution to the PN junction