H. Nishino et al., DISLOCATION PROFILES IN HGCDTE(100) ON GAAS(100) GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION, Journal of electronic materials, 24(5), 1995, pp. 533-537
We studied dislocation etch pit density (EPD) profiles in HgCdTe(100)
layers grown on GaAs(100) by metalorganic chemical vapor deposition. D
islocation profiles in HgCdTe(111)B and HgCdTe(100) layers differ as f
ollows: Misfit dislocations in HgCdTe(111)B layers are concentrated ne
ar the HgCdTe/CdTe interfaces because of slip planes parallel to the i
nterfaces. Away from the HgCdTe/CdTe interface, the HgCdTe(111)B dislo
cation density remains almost constant. In HgCdTe(100) layers, however
, the dislocations propagate monotonically to the surface and the disl
ocation density decreases gradually as dislocations are incorporated w
ith increasing HgCdTe(100) layer thicknesses. The dislocation reductio
n was small in HgCdTe(100) layers more than 10 mu m from the HgCdTe/Cd
Te interface. The CdTe(100) buffer thickness and dislocation density w
ere similarly related. Since dislocations glide to accommodate the lat
tice distortion and this movement increases the probability of disloca
tion incorporation, incorporation proceeds in limited regions from eac
h interface where the lattice distortion and strain are sufficient. We
obtained the minimum EPD in HgCdTe(100) of Ito 3 x 10(6) cm(-2) by gr
owing both the epitaxial layers more than 8 mu m thick.