| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a silicon wafer-based substrate which is suitable for forming a nitride semiconductor and is low in cost; and to provide a substrate for forming a nitride semiconductor which reduces the occurrence of a curvature and crack, which are caused by differences in lattice constant and thermal expansion coefficient between materials, even if a nitride semiconductor epitaxial layer whose film is large in thickness is grown, the substrate being excellent in mechanical strength and thermal strength. <P>SOLUTION: In a silicon wafer, boron and germanium are doped at a specific concentration. For a ratio in concentration of the boron to the germanium, the concentration of the germanium is controlled preferably to be 5-8 times as much as that of the boron. <P>COPYRIGHT: (C)2012,JPO&INPIT |
