Pt Schottky contacts to n-GaN formed by electrodeposition and physical vapor deposition

Electrodeposited, dc magnetron sputtered, and electron beam evaporated Pt c ontacts to n-GaN (n=1.5x10(17) cm(-3)) are reported. All contacts were rect ifying in the as-deposited condition, and values of the barrier height were determined by current-voltage (I-V) and capacitance-voltage (C-V) measurem ents. The influence of deposition conditions on the electrical characterist ics of the sputtered and electrodeposited Pt contacts was further studied. Additionally, a dependence of the barrier height with time following deposi tion is shown. Taking into consideration all parameters of this study, the barrier height could differ by as much as 0.65 eV by I-V measurements and 0 .64 eV by C-V measurements, with I-V and C-V barriers as high as 1.43 and 1 .57 eV, respectively. Reverse current densities are reported for a -5 V bia s with the highest and lowest median values differing by a factor of 10(4) as a result of the different deposition conditions. The electrical properti es are believed to be strongly influenced by the presence of electrically a ctive defects introduced during metal deposition. Deep level transient spec troscopy data support this hypothesis. (C) 2000 American Institute of Physi cs. [S0021-8979(00)07417-X].