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:
Jul. 07, 2009
Filed:
May. 18, 2006
Ting Sing Wang, Hsinchu, TW;
Ting Sing Wang, Hsinchu, TW;
Promos Technologies Inc., Hsinchu, TW;
Abstract
A recessed gate structure comprises a semiconductor substrate, a recess positioned in the semiconductor substrate, a gate oxide layer positioned in the recess and a conductive layer positioned on the gate oxide layer, wherein the semiconductor substrate has a multi-step structure in the recess. The thickness of the gate oxide layer on one step surface can be different from that on another step surface of the multi-step structure. In addition, the recessed gate structure further comprises a plurality of doped regions positioned in the semiconductor substrate under the multi-step structure, and these doped regions may use different dosages and different types of dopants. There is a carrier channel in the semiconductor substrate under the recessed gate structure and the overall channel length of the carrier channel is substantially the summation of the lateral width and twice of the vertical depth of the recessed gate structure.