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:
Nov. 24, 2009
Filed:
May. 25, 2006
Ting Sing Wang, Hsinchu, TW;
Ting Sing Wang, Hsinchu, TW;
Promos Technologies Inc., Hsinchu, TW;
Abstract
A multi-step gate structure comprises a semiconductor substrate having a multi-step structure, a gate oxide layer positioned on the multi-step structure and a conductive layer positioned on the gate oxide layer. Preferably, the gate oxide layer has different thicknesses on each step surface of the multi-step structure. In addition, the multi-step gate structure further comprises a plurality of doped regions positioned in the semiconductor substrate under the multi-step structure. The channel length of the multi-step gate structure is the summation of the lateral width and the vertical depth of the multi-step gate structure, which is dramatically increased such that problems originated from the short channel effect can be effectively solved. Further, the plurality of doped regions under the multi-step structure are prepared by implanting processes having different dosages and dopants, which can control the thickness of the gate oxide layer and the threshold voltage of the multi-step gate structure.