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
OG exemplary drawing
 
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.