Method for fabricating a multilayer epitaxial structure

US5324685A · kind A · utility

Inventors

• Reinhold Hirtz · Huntington, US
• Gregory Zakaluk · Seaford, US
• Joseph Chan · San Francisco, US
• Dennis Garbis · Huntington Station, US
• Lawrence LaTerza · Miller Place, US
• Ali Salih · Mesa, US

Key dates

• Filing date: Feb 9, 1993
• Grant date: Jun 28, 1994
• Expiry date: Feb 9, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/902
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

An all epitaxial process performed entirely in a CVD reactor is employed to grow heavily doped layer on lightly doped layer on a heavily doped substrate, eliminating the need for separate diffusion, even for high impurity concentrations. The process starts with a heavily doped silicon substrate of carrier concentration typically greater than 1.times.10.sup.19 per cm.sup.3. To minimize outdiffusion, the substrate is "capped" by growing very thin and heavily doped silicon layers which are depleted by hydrogen purges. A first epitaxial layer is grown over the "capped" substrate. This layer is relatively lightly doped, having a resistivity of more than 200 ohm.cm. A second epitaxial layer is then grown over the first epitaxial layer. The second epitaxial layer has a polarity opposite to that of the substrate and is heavily doped to a resistivity of less than 0.005 ohm cm.