Creation of high resistivity GaN by implantation of Ti, O, Fe, or Cr

Implantation of n- and p-type GaN with Ti+, O+, Fe+, or Cr+ was found to pr oduce defect levels which pinned the Fermi level in these materials at E-C- (0.20-0.49) eV (n type) or E-V + 0.44 eV (p type). Maximum sheet resistance s of similar to 10(12) Omega/square (n type) and similar to 10(10) Omega/sq uare (p type) were obtained after implantation and annealing in the range o f 300-600 degrees C. At higher annealing temperatures, the sheet resistance decreased to near the unimplanted values (3 x 10(4) Omega/square in p type , 7 x 10(2) Omega/square in n type). The evolution of the sheet resistance with annealing temperature is consistent with damage-related trap sites rem oving carriers from the conduction or valence bands. (C) 2000 American Inst itute of Physics. [S0021-8979(00)01603-0].