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Title: Influence of oxygen on segregation of chromium at structural damage in gallium arsenide

Technical Report ·
OSTI ID:5930754

Cr redistribution in presence of dislocations and 0 atoms in ion-implanted and furnace-annealed GaAs was studied by XTEM and SIMS. Cr-doped, semi-insulating (100) GaAs samples were self-implanted with 550-keV Ga and As ions at RT. Two different doses (4x10/sup 13/ cm/sup -2/ and 2x10/sup 15/ cm/sup -2/) of 0 were also implanted after the above implantation. Initial implantation damage in samples with or without oxygen consisted of continuous bands of amorphous and microtwinned material, respectively. Comparison of the TEM results from annealed samples (600 to 840/sup 0/C) with and without 0 showed that highly twinned and misoriented GaAs forms along with a network of densely entangled dislocations near the surface (O-R/sub p/) in the former case while only entangled dislocations by plastic deformation occur over the depth range O-R/sub p/ in the latter case. The deeper parts in both cases contained bands of dislocation loops, whose diameter became smaller with increasing amount of 0. SIMS showed redistribution of Cr and 0 in the implanted region and vicinity. In the samples without 0, there was a one-to-one correspondence between the positions of the damage layers and peaks in the atomic profile of Cr. However, in the presence of 0, such correlations became complicated. A model explaining the Cr redistribution in amorphous GaAs and Cr segregation to the defects is presented. The pronounced effect of 0 on Cr redistribution and retardation in the annealing out of dislocations has been explained by the formation of Cr-0 complexes during the annealing and their interaction with dislocations.

Research Organization:
Lawrence Berkeley Lab., CA (USA)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5930754
Report Number(s):
LBL-16190; ON: DE83014901
Resource Relation:
Other Information: Thesis
Country of Publication:
United States
Language:
English