| US 7,592,230 B2 | ||
| Trench power device and method | ||
| Edouard D. de Frésart, Tempe, Ariz. (US); and Robert W. Baird, Gilbert, Ariz. (US) | ||
| Assigned to Freescale Semiconductor, Inc., Austin, Tex. (US) | ||
| Filed on Aug. 25, 2006, as Appl. No. 11/510,552. | ||
| Prior Publication US 2008/0048258 A1, Feb. 28, 2008 | ||
| Int. Cl. H01L 21/336 (2006.01) | ||
| U.S. Cl. 438—272 [257/329] | 16 Claims |

| 1. A method for forming a semiconductor (SC) device, comprising:
providing a body of a first semiconductor material of a first composition and having an upper surface by
forming a pillar of an epi-growth mask layer material on an upper surface of a first semiconductor layer,
providing a first body region on exposed portions of the upper surface of the first semiconductor layer and in contact with
sides of the pillar, and
performing an etching process to selectively etch the pillar, resulting in a creation of a trench having sidewalls extending
from the upper surface of the body into the first semiconductor layer;
applying a second semiconductor material of a second, different, composition to form a higher mobility semiconductor material
at least on the sidewalls;
providing a first dielectric at least over the higher mobility semiconductor material;
placing a first conductor in the trench separated from the higher mobility semiconductor material by the first dielectric;
and
forming a first device region in the first portion of the body in the first semiconductor material, communicating with the
higher mobility semiconductor material and adapted to provide in response to a signal on the first conductor and a potential
difference between the first device region and the second portion, current flow from the first device region passing substantially
through the higher mobility semiconductor material to the second portion.
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