ON EPITAXIAL SI1-XGEX THIN-FILM GROWTH BY CHEMICAL-VAPOR-DEPOSITION FROM A SILANE, GERMANE, HYDROGEN-CHLORIDE AND HYDROGEN GAS-MIXTURE

Epitaxial Si1-xGex layers were deposited in a conventional atmospheric pressure process from silane, germane, hydrogen chloride and hydrogen gas mixtures in the temperature range from 1070 to 730-degrees-C. A c lear transition from strong to weak temperature dependence is observed at about 870-degrees-C as typical for pure silicon deposition from si lane. So a transport-reaction limited mechanism is deduced for Si-Ge l ayer growth. The theoretical consideration of growth mechanism is base d on the assumption of three partial growth rates, the sum of which is equal to total layer growth rate. The partial growth rates consist of the silicon growth rate observed without germane in the gas, the germ anium growth rate observed by the presence of germane in the gas, and the rate of additional silicon deposition caused by the presence of ge rmane, too. Germanium partial growth rate is also characterized by a s trong and weak region of temperature dependence; however, the transiti on is observed at about 980-degrees-C.