Thermal Modification of a-SiC:H Films Deposited by Plasma EnhancedChemical Vapour Deposition from CH4+SiH4 Mixtures

Abstract

The effects of thermal annealing on photoluminescence (PL) and structuralproperties of a-Si1-xCx:H films deposited by plasma enhancedchemical vapour deposition from CH4+SiH4 mixtures are studied byusing infrared, PL and transmittance-reflectance spectra. In a-SiC:Hnetwork, high-temperature annealing gives rise to the effusion of hydrogenfrom strongly bonded hydrogen in SiH, SiH2, (SiH2)n, SiCHn and CHnconfigurations and the break of weak C-C, Si-Si and C-Si bonds. Astructural rearrangement will occur, which causes a significantcorrelation of the position and intensity of the PL signal with theannealing temperature. The redshift of the PL peak is related to thedestruction of the confining power of barriers. However, the PL intensitydoes not have a significant correlation with the annealing temperature fora C-rich a-SiC:H network, which refers to the formation of π-bondcluster as increasing carbon content. It is indicated that the thermalstability of C-rich a-Si1-xCx:H films is better than that ofSi-like a-Si1-xCx:H films. PACS: 78. 55. Hx, 78. 66. Jg, 61. 43. Dq