Method for preparing an N+PP+ or P+NN+ structure on silicon wafers

摘要

The present invention relates to a method for preparing, on a silicon wafer, an n+pp+ or p+nn+ structure which includes the following consecutive steps: a) on a p or n silicon wafer (1), which includes a front surface (8) and a rear surface (9), a layer of boron-doped silicon oxide (BSG) (2) is formed on the rear surface (9) by PECVD, followed by a SiOx diffusion barrier (3); b) a source of phosphorus is diffused such that the phosphorus and the boron co-diffuse and in order also to form: on the front surface (8) of the wafer obtained at the end of step a), a layer of phosphorus-doped silicon oxide (PSG) (4) and an n+ doped area (5); and on the rear surface of the wafer obtained at the end of step a), a boron-rich area (BRL) (6), as well as a p+ doped area (7); c) the layers of BSG (2) and PSG (4) oxides and SiOx (3) are removed, the BRL (6) is oxidized and the layer resulting from said oxidation is removed. The invention also relates to a silicon wafer having an n+pp+ or p+nn+ structure, which can be obtained by said preparation method, as well as to a photovoltaic panel manufactured from such a silicon wafer.

主权项

1. A method for preparing a structure of type n+pp+ or type p+nn+ on a silicon wafer, comprising the following successive steps:
a) on a silicon wafer of type p or type n which comprises a front surface and a back surface, PECVD is conducted to form on a back surface a layer of boron-doped silicon oxide (BSG), then depositing a SiOx diffusion barrier layer on the boron-doped silicon oxide (BSG); b) a phosphorus source is diffused so that the phosphorus and boron co-diffuse and so as also to form:
on the front surface of the wafer obtained after step a):
a phosphorus-doped silicon oxide layer (PSG),a n+ doped regionand on the back surface of the wafer obtained after step a):
a boron rich layer (BRL), anda p+ doped region; c) the BSG, PSG and SiOx layers are removed, the BRL is oxidized and the oxidized BRL layer is removed.