Silicon epitaxy by low-temperature RF-PECVD using SiF4/H2/Ar gas mixtures for emitter formation in crystalline solar cells

This paper describes ongoing studies on the emitter formation by PECVD (Plasma Enhanced Chemical Vapor Deposition) using SiF4/H2/Ar chemistry in crystalline silicon solar cells. H2 depletion and ion bombardment have been highlighted to be crucial factors to sustain epitaxial growth. By controlling these parameters we have been able to produce a 2.5μm-thick high-quality silicon epitaxy and to define a process window. Structural properties were assessed by in-situ and exsitu spectroscopic ellipsometry as well by HR-TEM (High Resolution Transmission Electron Microscopy) images with the diffraction patterns. These studies have been extended to n-type and p-type doped layers.