CONTACT MATERIALS FOR GaSb AND InSb: A PHASE DIAGRAM APPROACH

The development of well defined and thermally stable ohmic contacts for III-V semiconductors like InSb and GaSb is still a challenging problem in semiconductor device technology. As device processing usually includes the exposure to elevated temperatures, interface reactions often occur during metallization and further heat treatment. It is thus important to understand the respective phase equilibria of the involved elements. From the thermodynamic point of view, binary and ternary compounds in equilibrium with the respective compound semiconductor would be the best choice for contact materials as these contacts will be stable even after long exposure to elevated temperatures. These possible candidates for contact materials may be directly obtained from the phase diagrams. During the last years we investigated several phase diagrams of transition metals with GaSb and InSb. Experimental results in the systems Ga-Ni-Sb, Ga-Pd-Sb, Ga-Pt-Sb, In-Ni-Sb and In-Pd-Sb are summarized and are discussed in the context of contact chemistry.