Abstract :
The total thickness and composition of a residual oxide layer after chemical etching of p-GaAs:Zn + In has been studied
by X-ray photoelectron spectroscopy (XPS). The variation of the Ga to As oxides ratio along the depth has been determined.
A concentration correlation of doping isovalent impurity and the dislocation density with the composition of residual oxides
is looked for. The total thickness of the residual oxide layer on p- and semi-insulating GaAs is about 5-6 A. It is found that
the Ga203 quantity in the oxide bulk is greater than the same value of As203 in highly In-doped samples. In-doping in
concentrations over 1.5 × 1019 cm -3 increases the Ga203 content and the density of the residual oxide. This influence is
determined by reducing the dislocation density and changing the point defect environment. The presence of As-rich
precipitates on the dislocations and in the matrix decreases the sputtering time and changes the composition of the residual
oxide. The correlation between the type of high temperature dislocations revealed by Abrahams-Buiocchi (AB) etching and
the oxide layer composition is shown. The results obtained could be used in the first stages of epitaxial growth, metallization
and other technological processes of semiconductor device and ICs fabrication. © 1997 Elsevier Science B.V.
