In situ monitoring of growth rate parameters in hot-wire assisted gas source-molecular beam epitaxy using a quartz microbalance

We have measured, in situ, the growth rate of low pressure chemical vapour deposition silicon or germanium films under hot-wire conditions using a quartz microbalance. The decomposed gases are disilane and germane at a pressure in the 10−4 to 10−5 mbar range. The gas source decomposition was achieved by a hot tungsten filament. The effects of filament temperature and gas pressure on the deposition rate are investigated and the role of primary radicals discussed. Efficient decomposition of feed gases without tungsten film contamination was obtained for a filament temperature of 1800 K. We show that films deposited at room temperature on Si(001) substrate are amorphous. Films prepared at 620 K are well ordered and exhibit good crystalline qualities.