Box-method boron microcrystalline glass source concentrated boron diffusion method

Abstract

The invention provides a box-method boron microcrystalline glass source concentrated boron diffusion method which comprises the steps of S1) carrying out high-temperature pretreatment on boron microcrystalline glass to obtain pretreated boron microcrystalline glass; S2) stacking the pretreated boron microcrystalline glass and a silicon wafer to be subjected to diffusion treatment, and heating for diffusion treatment to obtain a treated silicon wafer, wherein the front surface of the silicon wafer to be subjected to diffusion treatment is in contact with the pretreated boron microcrystalline glass; and S3) removing borosilicate glass on the surface of the treated silicon wafer to obtain the silicon wafer subjected to boron diffusion treatment. Compared with the prior art, the PWB source is in direct contact with the Si wafer, so that a shallow junction can be formed while high surface concentration is realized; secondly, the upper surface and the lower surface of the PWB source can be in contact with the to-be-doped surfaces of the two layers of Si wafers respectively, so that the diffusion efficiency is improved; moreover, the method provided by the invention only uses one-step diffusion, does not need to take out the Si wafer midway for treatment, is simple in process and easy to operate, and avoids unnecessary pollution.

Description

Technical field [0001] The present invention belongs to the microwave semiconductor technology, and in particular, the present invention relates to a method of dip boron diffusion of boron microcrystalline glass sources. Background technique [0002] Microwave semiconductor diffusion process technology is divided into: constant surface source diffusion and defining surface source diffusion. Under ideal, when the constant surface source diffuses, the impurity concentration is distributed in the depth of the surface, the surface concentration is always constant, and the time is independent; the concentration of the diffusion impurities defining the surface source is Gaussian distribution, when the diffusion temperature is maintained When constant, as the diffusion time increases, the concentration of surface impurities continues to decrease, but the total amount of diffusion impurities remain unchanged. [0003] In terms of boron diffusion sources of p-type dopants, trimethylation,...

AI Technical Summary

Problems solved by technology

[0005] However, the open-tube diffusion method has a long and complicated process flow, and the main diffusion used is limited surface source diffusion. When it is applied to the process of low-voltage PIN diodes, the junction depth can be controlled, but when impurities are redistributed (main diffusion) , the surface concentration is not as high as the box method concentrated boron diffusion method (constant surface source diffusion), which can only reach 6×10 18 cm -3 , Insufficient surface concentration will affect the ohmic contact on the product surface, which will greatly affect the product parameter performance indicators, which in turn will affect the parameters of the product series resistance in the PIN diode technical indicators

Images