| US 7,449,380 B2 | ||
| Method of fabricating isolated semiconductor devices in epi-less substrate | ||
| Richard K. Williams, Cupertino, Calif. (US); Michael E. Cornell, Campbell, Calif. (US); and Wai Tien Chan, Fanling (China) | ||
| Assigned to Advanced Analogic Technologies, Inc., Santa Clara, Calif. (US); and Advanced Analogic Technologies (Hong Kong) Limited, Hong Kong (China) | ||
| Filed on Feb. 25, 2005, as Appl. No. 11/67,247. | ||
| Application 11/067247 is a continuation of application No. 10/218668, filed on Aug. 14, 2002, granted, now 6,900,091, filed on May 31, 2005. | ||
| Prior Publication US 2005/0142791 A1, Jun. 30, 2005 | ||
| Int. Cl. H01L 21/8238 (2006.01) | ||
| U.S. Cl. 438—207 | 4 Claims |
| 1. A process of fabricating a semiconductor device comprising:
providing a semiconductor substrate of a first conductivity type, the substrate not containing an epitaxial layer;
forming a mask layer on a surface of the substrate;
patterning the mask layer to form an opening;
implanting a dopant of a second conductivity type into the substrate through the opening at an energy sufficient to form a
submerged layer, the submerged layer being completely submerged in the semiconductor substrate;
after forming the submerged layer, forming a trench extending downward from the surface of the substrate into the submerged
layer;
introducing a dielectric material into the trench, the trench and the submerged layer forming an isolation structure and enclosing
an enclosed region of the first conductivity type above the submerged layer.
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