Ni, Pd, or Pt as contact materials for GaSb and InSb semiconductors: Phase diagrams

As processing, and even use, of semiconductor devices usually includes the exposure to elevated temperatures, interface reactions often occur, especially during metallization and further heat treatment. It is thus important to understand the corresponding phase equilibria of the involved elements. We present here the phase diagrams of Ni, Pd, and Pt with GaSb and InSb; experimental results in the systems Ga-M-Sb and In-M-Sb (M = Ni, Pd, Pt) are summarized and are discussed in the context of contact chemistry. For GaSb and InSb, it is found that, from a thermodynamic point of view, binary and ternary compounds in equilibrium with the corresponding semiconductor would be the best choice for contact materials as these contacts will remain stable even after long exposure to elevated temperatures.