US 7,320,925 B2
SOI substrate, semiconductor substrate, and method for production thereof
Tsutomu Sasaki, Hikari (Japan); Seiji Takayama, Hikari (Japan); and Atsuki Matsumura, Hikari (Japan)
Assigned to Siltronic AG, Munich (Germany)
Filed on Jun. 02, 2004, as Appl. No. 10/858,646.
Claims priority of application No. 2003-170093 (JP), filed on Jun. 13, 2003; and application No. 2003-333908 (JP), filed on Sep. 25, 2003.
Prior Publication US 2004/0253793 A1, Dec. 16, 2004
Int. Cl. H01L 21/84 (2006.01)
U.S. Cl. 438—407  [257/E21.561] 17 Claims
OG exemplary drawing
 
1. A method of producing a semiconductor substrate of single crystal silicon having a buried silicon compound partial film, said method comprising the steps of:
a) forming an ion implantation mask on a surface of a single crystal silicon substrate;
b) implanting non-silicon atoms beneath the surface of the single crystal silicon substrate by ion implantation through the mask in a direction not perpendicular to the surface of the single crystal silicon substrate, wherein at least two angles are formed between a projection of the flux of ion implantation and a specific azimuth of the substrate; and
c) heat treating the substrate at a temperature of not less than 1250° C. for not less than ten minutes.