Investigations of trace analysis of A(III)B(V) semiconductor microsamples by atomic spectroscopy-VII Investigation of trace and thin-layer analysis of doping elements (Ag, Au, Bi, Cd, Sn, Tl) in InAs by atomic-absorption with electrothermal evaporation

Etching procedures for separation of thin layers of InAs (up to 1.4 mum thick) have been developed and optimized. A solid-state microtome has been used for cutting layers thicker than 1mum. AAS/ETA methods for determination of traces of Ag, Au, Bi, Cd, Sn, and Tl have been developed. The matrix interferences of nitric add, hydrobromic acid, and As(3+) or In(3+) in nitric or hydrobromic acid have been studied. The main causes of the matrix interference are the formation of diatomic molecules between the trace and matrix components, and the effect of the evaporation processes. By use of the platform technique with special platforms some matrix interferences could be minimized. For the determination of traces of Sn, matrix modification with Ni(NO(3))(2) as additive gave the best analytical values. For the trace determination of Au, separation of In from Au by evaporation of InBr(3) from 0.6M HBR medium in the AAS ashing phase was developed. The detection limits are in the 10(16) atoms/cm(3) region for layers of 1 mum thickness and surface area 1 cm(2).