| 摘要 |
PURPOSE:To obtain a wafer, in which there are few crystal defects and in a diffusion region therein inequality is not generated, by using a poly-boron film (PBF) by changing over gases at a first step and a second step in an atmosphere in a diffusion furnace and controlling time at the first step. CONSTITUTION:A PBF5 is applied on a wafer 4 in which an SiO2 layer 2 is formed on an Si substrate 1. A quartz pipe 13 is put into a diffusion furnace 11, and N2 and O2 are forwarded, and the PBF layer 5 is burnt to form a boron glass layer 6. When a temperature is elevated to 900 deg.C, boron is diffused into the substrate 1 from the boron glass layer 6, and a boron diffusion region 7 is shaped. The generation of the inequality of projections at both ends of the bottom of the boron diffusion region 7 and an extent in the lateral direction is inhibited because said first process is executed for approximately 10min or 2hr and boron is supplied uniformly from the boron glass layer 6 in a short time. When a temperature is elevated to 1,100 deg.C and gases, etc. are changed over to O2 in a second process, diffustion from the boron glass layer 6 is stopped, and shifted to the extending diffusion only of the inside of the boron diffusion region 7. |
