The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 14, 2009
Filed:
Sep. 25, 2007
Bing-yue Tsui, Hsinchu, TW;
Bing-Yue Tsui, Hsinchu, TW;
Episil Technologies Inc., Hsinchu, TW;
Abstract
A method of fabricating an MOS device is described. A substrate doped a first type dopant is provided as a drain. A first type epitaxial layer is formed on the substrate and is patterned with a trench to form several islands. A gate dielectric layer is then formed on the surface of the trench, and a gate is formed in the trench covering the gate dielectric layer. A second type dopant is doped into the islands with the doping concentration decreasing gradually from the bottom to the top of the islands. Afterwards, a source is formed at the top of the islands. Accordingly, the doping concentration in the islands decreases gradually from the drain to the source with the highest doping concentration near the drain. Therefore, the width of the depletion region can be reduced, and the length of the device channel can be reduced for lowering channel resistance and gate capacitance.