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:
Oct. 19, 1999
Filed:
Dec. 03, 1996
Huang-Chung Cheng, Hsinchu, TW;
Han-Wen Liu, Hsinchu, TW;
Stewart Huang, Hsinchu, TW;
Roger Yen, Hsinchu, TW;
Mosel Vitelic Inc., Hsinchu, TW;
Abstract
A porous silicon layer is created by using wet etching to etch a polysilicon layer. In preferred embodiment, the polysilicon layer is treated by H.sub.3 PO.sub.4 solution at 60-165.degree. C. for about 3-200 minutes. The porous silicon layer is subsequently treated by using a SC-1 solution at a temperature about 50-100.degree. C. for about 5-30 minutes to form a roughened polysilicon layer. The SC-1 solution is composed of NH.sub.4 OH, H.sub.2 O.sub.2 and H.sub.2 O. The volume ratio for the three compounds of said SC-1 is NH.sub.4 OH:H.sub.2 O.sub.2 :H.sub.2 O=0.1-5:0.1-5:1-20. The next step of the formation is the deposition of a dielectric film along the roughened surface of the micro-islands polysilicon layers. A conductive layer is deposited over the dielectric film. Next, photolithgraphy and etching process are used to etch the conductive layer, the dielectric film and the micro-islands polysilicon layer into a portion of the layer.