Phase relationships in the ternary Ga-Ni-Sb system

Undesirable chemical reactions between metal contacts and a semiconductor s ubstrate may be prevented by selecting metallization layers which are in th ermodynamic equilibrium with the substrate. In order to determine the react ion products resulting from the formation of the Ni-GaSb contact, phase equ ilibria in the Ga-Ni-Sb system have been established experimentally at 500, 600 and 900 degrees C. For the compound semiconductor GaSb negligible soli d solubility of Ni was measured both at 500 and 600 degrees C. In an attemp t to clarify the existence of the ternary E-phase in this system, a number of alloys with various compositions were prepared, equilibrated, and examin ed by XRD, EPMA, and optical microscopy. In addition, the variation of the lattice parameters of the a-phase was determined as a function of compositi on at 900 degrees C; the results are discussed in terms of the filling of t he different lattice positions of the hexagonal unit cell. (C) 2000 Elsevie r Science S.A. All rights reserved.