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:
Jan. 14, 1992
Filed:
Apr. 24, 1989
Mark N Ruberto, New York, NY (US);
Alan E Willner, New York, NY (US);
Richard M Osgood, Jr, Chappaqua, NY (US);
Dragan V Podlesnik, New York, NY (US);
The Trustees of Columbia University in the City of New York, New York, NY (US);
Abstract
The sensitivity of localized photochemical etching to the optical and electrical properties of multilayered semiconductor materials is utilized for selectively etching a laterally extending undercut in a buried layer. The semiconductor body is immersed in a suitable etching solution and a beam of light of appropriate wavelength and intensity is directed onto the semiconductor solution interface. The buried layer has a longer diffusion length for photogenerated carriers than the layers adjacent thereto, casuing carriers to diffuse away from the illuminated region within the buried layer and thereby etch the buried layer laterally, undercutting the adjacent layers.