Effects of Hot Wire Temperature on Properties of GeSi:H Films with High Hydrogen Dilution by Hot-Wire Chemical Vapor Deposition

摘要

GeSi:H films are prepared by hot-wire chemical vapor deposition(CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature(Tw) on deposition rate, structural properties and bandgap of GeSi:H films are studied with surface profilemeter, Raman spectroscopy, Fourier transformed infrared spectroscopy, and UV-VIS-NIR spectrophotometer. It is found that the deposition rate(Rd) goes up with increasing of Tw, but increasing rate of Rd declines when Tw≥1 550 ℃. High Tw is beneficial to the formation of Ge-Si, but it has little effect on relative contents of the hydrogen bonds(Ge-H, Si-H, etc.) in the films. In the Tw range of 1 400-1 850 ℃, the maximum bandgap of the GeSi:H films is 1.39 eV at Tw =1 450 ℃ and the band gap decreases with Tw increasing when Tw≥1 450 ℃.