Alternative (Pd,Ti,Au) contacts to (Pt,Ti,Au) contacts for In0.53Ga0.47As

(Pd,Ti,Au) contacts, Ti/Pd/Au and Pd/Ti/pd/Au, to In0.53Ga0.47As have been investigated for applications in InP-based devices. A thin interfacial Pd layer, with an optimum thickness of similar to 100 Angstrom, was found to be essential in contact to p(+)-In0.53Ga0.47As but undesirable to n(+)-In0.53Ga0.47As. Pd (100 Angstrom)/Ti (200 Angstrom)/Pd (200 Angstrom)/Au (2000 Angstrom) and Ti (200 Angstrom)/Pd (200 Angstrom)/Au (2000 Angstrom) yielded, respectively, a minimum specific contact resistance (rho(c)) of 1.68x10(-6) Ohm cm(2) and 2.54 x 10(-7) Ohm cm(2) to p(+) - and n(+)-In0.53Ga0.47As (p(+) = n(+) = 1 x 10(19) cm(-3)). (Pd,Ti,Au) contacts have shown to outperform (Ti,Pt,Au) counterparts in rho(c). In addition, it has been seen that contact anneal beyond 400 degrees C should be avoided for thin base InP-based heterojunction bipolar transistors. (C) 1998 American Institute of Physics. [S0021-8979(98)06617-1].