STUDY OF P-μc-Si1-xGex :H THIN FILM BY VHF-PECVD

摘要

In this paper, a series of boron doped microcrystalline hydrogenated silicon-germanium (P-μc-Si1-xGex:H) was deposited by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) at different GeF4 concentration (GC=[GeF4]/[GeF4]+[SiH4]). The Ge fraction x was measured by XRF and the conductivity was measured by the coplanar conductivity measurement. The results showed that, with the increasing of GC, the Ge fraction x increases slowly first, then increases linearly and the dark conductivity increases first, then decreases. The results of Raman measurement evidently showed that the crystalline volume fraction of p-type microcrystalline silicon germanium increased small and then decreased as the GC increased. When the GC is 4%, p-μc-Si1-xGex:H material with high conductivity, low activation energy (σ＝ 1.68S/cm ，Eg＝0.047ev ) and high crystalline volume fraction at the thickness of 72nm was achieved. The experimental results were discussed in detail.