IN-SITU DOPED SILICON VIA LPCVD; INTERACTIONS OF THE DOPANT/SILANE/SILICON SURFACE SYSTEM.

Abstract

Low Pressure Chemical Vapor Deposition (LPCVD) is widely used for the deposition of intrinsic (undoped) polycrystalline silicon thin films. The extension of this technique to the preparation of in-situ doped films requires the introduction of dopant bearing precursor molecules such as phosphine (PH//3) for n-type material or diborane (B//2H//6) for p-type material. If deposited by standard LPCVD techniques, and depending upon the dopant utilized, resulting films are of poor quality (i. e. non-uniform both physically and chemically). Using a variety of UHV surface probes (LEED, AES, and SIMS), the authors examine the interaction of these dopant species with silane at the growth interface, and correlate their measurements with phenomena observed during the LPCVD process.