A low resistivity ohmic contact to poly-GaN was achieved using the multilayer metal combination of Ti (50 angstrom)/Au (100 angstrom)/Ni (100 angstrom)/Au (3000 angstrom). Exactly how rapid thermal annealing (RTA) affects the specific contact resistivity (rho(c)) was also studied by varying the temperature and duration of annealing. An improvement in rho(c) of over one order of magnitude was achieved over the as-deposited condition with good reproducibility by RTA treatment for a total duration of 120 s. In particular, by optimizing the annealing temperature to 400 degrees C a relatively low rho(c) of 1.6 x 10(-5) Omega cm(2) was yielded for the contact of Ti/Au/Ni/Au to poly-GaN with a carrier concentration of (5-6) x 10(17) cm(-3). Related mechanism for the improvement in rho(c) was discussed based on the results obtained from X-ray diffraction analysis and transmission electron microscopy observations. (C) 2007 Elsevier Ltd. All rights reserved.