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.