THERMAL-STABILITY OF W, WSIX, AND TI AL OHMIC CONTACTS TO INGAN, INN,AND INALN/

W, WSi0.44, and Ti/Al contact properties were examined on n(+)In(0.65) Ga(0.35)N, InN, and In0.75Al0.25N. W was found to produce low specific contact resistance (rho(c) similar to 10(-7) Omega cm(2)) ohmic conta cts to InGaN, with significant reaction between metal and semiconducto r occurring at 900 degrees C mainly due to out diffusion of In and N. WSix showed an as-deposited rho(c) of 4 x 10(-7) Omega cm(2) but this degraded significantly with subsequent annealing at greater than or eq ual to 600 degrees C. Ti/Al contacts were stable to similar to 600 deg rees C (rho(c) similar to 4 x 10(-7) Omega cm(2) at less than or equal to 600 degrees C). The surfaces of these contacts remained smooth to 800 degrees C for W and WSix and 650 degrees C for Ti/Al. InN contacte d with W and Ti/Al produced ohmic contacts with rho(c) similar to 10(- 7) Omega cm(2) and for WSix rho(c) similar to 10(-6) Omega cm(2). All remained smooth to similar to 600 degrees C, but exhibited significant interdiffusion of In, N, W, and Ti, respectively, at higher temperatu res. The contact resistances for all three metalization schemes were g reater than or equal to 10(-4) Omega cm(2) on InAlN, and degraded with subsequent annealing. (C) 1996 American Vacuum Society.