Strain relaxation and surface roughness as a function of growth temperature in linearly graded In(x)Al(1-x)As (x=0.05 to 0. 25) buffers.

摘要

The relation of relaxation to surface morphology in linearly-graded InAlAs was examined as a function of growth temperature using x-ray diffraction and atomic force microscopy (AFM). Samples were grown at temperatures ranging from 370 to 550C. Weak diffraction features for samples grown at 370 and 420C limited determination of the extent of their relaxation. The fractional relaxation of samples grown between 470 to 550C was essentially identical ((approximately)77%) and symmetric in orthogonal directions. The character of the surface morphology changed from random small scale roughness to a roughness more periodic in nature as the growth temperature increased. Although no asymmetry was observed in the relaxation, the roughness developed an asymmetry at higher growth temperatures with more prominent ridges along ((bar 1)10-(1(bar 1)0).