Mechanism of growth of the Ge wetting layer upon exposure of Si(100)-2 x 1 to GeH4.
This paper describes the initial reaction kinetics of Ge deposition after exposure of Si(100)-2 x 1 to GeH4 in a UHV-CVD system. The rate of Ge growth, especially at the wetting layer stage, was investigated using in situ X-ray photoelectron spectroscopy to measure the Ge signal at the onset of deposition. A kinetic analysis of the initial growth of the Ge wetting layer at temperatures ranging from 698 to 823 K revealed an activation energy of 30.7 kcal/mol. Density functional theory calculations suggested that opening of the Si dimer--with a closely matching energy barrier of 29.7 kcal/mol, following hydrogen atom migration--was the rate controlling step for the incorporation of a GeH2 unit into the lattice to complete the growth of the Ge wetting layer after dissociative adsorption of GeH4.
Liu
Chie-Sheng
CS
Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Keelung Road, Section 4, Taipei, 106, Taiwan.
Chou
Li-Wei
LW
Hong
Lu-Sheng
LS
Jiang
Jyh-Chiang
JC