IN-SITU MONITORING OF GROWTH-RATE PARAMETERS IN HOT-WIRE ASSISTED GASSOURCE-MOLECULAR BEAM EPITAXY USING A QUARTZ MICROBALANCE

We have measured, in situ, the growth rate of low pressure chemical va pour deposition silicon or germanium films under hot-wire conditions u sing a quartz microbalance. The decomposed gases are disilane and germ ane at a pressure in the 10(-4) to 10(-5) mbar range. The gas source d ecomposition was achieved by a hot tungsten filament. The effects of f ilament temperature and gas pressure on the deposition rate are invest igated and the role of primary radicals discussed. Efficient decomposi tion of feed gases without tungsten film contamination was obtained fo r a filament temperature of 1800 K. We show that films deposited at ro om temperature on Si(001) substrate are amorphous. Films prepared at 6 20 K are well ordered and exhibit good crystalline qualities.