Surface Passivation for Heterojunction Silicon Wafer Solar Cells

Abstract

This thesis focuses on the development and analysis of surface passivating silicon alloys for heterojunction silicon wafer solar cell applications. As the narrow process window of conventional intrinsic amorphous silicon limits its industrial applicability, an alternative material that excels in both passivation quality and industrial compatibility is required. By using a new structure that consists of remote inductively coupled plasma deposited amorphous silicon suboxide thin films on low-resistivity n-type Czochralski silicon wafers, a state-of-the-art passivation quality with an extremely wide process window is demonstrated compared to other high-quality passivation schemes. A detailed understanding of the film properties and the deposition mechanisms is obtained by a sequence of electrical and structural measurements as well as computer simulations. A comparison between films deposited with capacitively and inductively coupled plasmas is also performed to demonstrate the advantage of the inductive method for passivation layer deposition of heterojunction solar cells.