Low-Resistance and Thermally Stable Pd/Ru Ohmic Contacts to p-Type GaN
Authors: Jang, Ja-Soon; Lee, Chang-Won; Park, Seong-Ju; Seong, Tae-Yeon; Ferguson, I.T.
Source: Journal of Electronic Materials, Volume 31, Number 9, 1 September 2002 , pp. 903-906(4)
Abstract:We report on low-resistance and thermally stable Pd/Ru ohmic contacts to surface-treated p-GaN (3 × 1017 cm-3). It is shown that annealing at 500°C for 2 min in a N2 ambient improves ohmic contact properties. Specific contact resistance is measured to be 9.2(±0.2) × 10-4 and 2.4(±0.2) × 10-5 Ωcm2 for the as-deposited and annealed samples, respectively. Atomic force microscopy results show that the surfaces of both the contacts are remarkably smooth with a root-mean-square (rms) roughness of about 0.6 nm. The current-voltage temperature (I-V-T) and calculation results indicate that, for the as-deposited contact, thermionic field emission is dominant, while for the annealed contact, field emission dominates the current flow.
Document Type: Miscellaneous
Publication date: 2002-09-01