Rl. Naone et La. Coldren, SURFACE-ENERGY MODEL FOR THE THICKNESS DEPENDENCE OF THE LATERAL OXIDATION OF ALAS, Journal of applied physics, 82(5), 1997, pp. 2277-2280
The lateral oxidation rate of AlAs layers decreases dramatically for l
ayers thinner than about 500 Angstrom, because the activation energies
for the rate constant of the reaction at the oxidation front increase
s by an amount inversely proportional to the layer thickness. We deriv
e a model for the thickness dependence of the lateral oxidation rate o
f AlAs based on the surface energy of the curvature observed at the ox
ide tip. From the model, we show that the linear oxidation rate has an
exp(-theta(0)/theta) dependence on the AlAs layer thickness theta, an
d we can predict the slowing of oxidation when the AlAs layer is cladd
ed with AlGaAs barriers. Also, we estimate the surface energy of the A
lAs/oxide interface to be 50 eV/nm(2). (C) 1997 American Institute of
Physics.