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. 12, 1999
Filed:
Sep. 22, 1997
Ming-Kwei Lee, Kao Hsiung, TW;
Yu-Hsiung Wang, Kao Hsiung, TW;
National Science Council, Taipei, TW;
Abstract
The present invention provides a method for forming porous silicon, which includes the steps of: a) providing a silicon substrate; b) growing a GaAs layer on the silicon substrate; c) defining a pattern for the GaAs layer by a photolithography process and etching the patterned GaAs layer to obtain a GaAs mask; and d) forming a porous silicon layer by anodic-oxidation-etching the silicon substrate uncovered by the GaAs mask. By this method, etching under the GaAs layer on the silicon substrate can be executed very well to form the porous silicon. And the patterned GaAs layer is etched by a process in step c), which is selected from a wet etching and a dry etching process with a photoresist as a mask. In addition, the anodic-oxidation-etching process in step d) is an electrolytic process executed in HF acidic solution which is a mixture of 30 vol. % HF and 70 vol. % H.sub.2 O, in which the HF concentration is 49 wt. %.