| 摘要 |
<p>A substrate suitable for use in a semiconductor device is prepared by subjecting the impurities in a substrate (1) at a lower concentration to diffusion, to form a more concentrated impurity layer at the opposed surfaces, and part of the thickness of the substrate is removed to expose a layer doped with the impurity at the lower concentration on one surface (B). The thus exposed surface is polished to provide the producting, having a varying concentration of impurities. The edges are bevelled at different angles ( theta theta ), before or after diffusion.</p> |
