| 摘要 |
<p>A buffer layer (2), an SiGe layer (3), and an Si cap layer (4) are formed over an Si substrate (1). By creating a mask on the substrate and carrying out patterning, a trench (7a) which reaches the Si substrate (1) and in which the side of the SiGe layer (3) is exposed is formed. The side of the trench (7a) is subjected to a heat treatment at 750° C for an hour, and thereby Ge contained in the surface portion of the SiGe layer (3) evaporates. As a result, a Ge evaporation region (8) having a Ge content lower than those of the other regions of the SiGe layer (3) is formed near the exposed portion of the SiGe layer (3) exposed in the trench (7a). Thereafter the side of the trench (7a) is oxidized.</p> |
