DEPOSITION OF 3-DIMENSIONAL GE ISLANDS ON SI(001) BY CHEMICAL-VAPOR-DEPOSITION AT ATMOSPHERIC AND REDUCED PRESSURES

This report summarizes observations of Ge island formation during grow th on Si(001) by chemical vapor deposition from germane in the pressur e range from 10 Torr to atmospheric pressure in a conventional epitaxi al reactor. A four-step growth process is observed: (1) uniform pseudo morphic overlayer (''wetting'' layer) formation; (2) three-dimensional island growth with a constant aspect ratio; (3) continued island grow th with a constant diameter and increasing height; (4) rapid growth of larger, faceted islands. Ostwald ripening of the islands during conti nued heat treatment after terminating the deposition is slow compared to island formation and growth during deposition for the experimental conditions used. (C) 1997 American Institute of Physics.