Method of localized photohemical etching of multilayered semiconductor body

US5081002A · kind A · utility

Assignee

• The Trustees of Columbia University in the City of New York · US

Inventors

• Mark Ruberto · Haifa, IL
• Alan E. Willner · Los Angeles, US
• Richard M. Osgood, Jr. · Chappaqua, US
• Dragan Podlesnik · Palo Alto, US

Key dates

• Filing date: Apr 24, 1989
• Grant date: Jan 14, 1992
• Expiry date: Apr 24, 2009

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/30612
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

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.