Abstract: 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.

Abstract: 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 oxidised and the layer resulting from said oxidation is removed.