Preparation and properties of high quality crystalline silicon films grown by ECR plasma deposition

Abstract

A process for growing high quality epitaxial silicon on heavily doped silicon (100) wafers at temperatures below 525/spl deg/C has been developed using a high vacuum electron cyclotron resonance (ECR) plasma deposition system. Plasma diagnostic work was done in order to optimize the growth conditions. The crystalline quality of our films has been verified using TEM, Raman and UV reflectance. Spreading resistance profiles (SRP) indicate that our undoped films are n-type with free carrier concentrations between 3/spl times/10/sup 16/ cm/sup -3/ and 3/spl times/10/sup 17/ cm/sup -3/. The junction between the heavily doped wafer and the undoped epi layer is shown to be abrupt. The mobilities of the carriers were measured using Hall measurements, and were found to be as high as in the best crystalline materials. This new technique may have significant applications for low cost Si solar cells.