Abstract
The possible origins of leaky characteristics of Schottky barrier on p-GaN have been investigated. The as-grown samples did not show any electrical activities using Hall measurements. Ni diodes made on as-activated samples, either at 950 °C for 5 s or at 750 °C for 5 min exhibited quasiohmic behavior. Upon sequential etching of the sample to remove a surface layer of 150 Å, 1200 Å, and 5000 Å from the sample, the I-V behavior became rectifying. I-V-T measurements showed that the slopes of the lnI-V curves were independent of the temperature, indicative of a prominent component of carrier tunneling across the Schottky junction. C-V measurements at each etch-depth indicated a decreasing acceptor concentration from the surface. The highly doped (>1.7 × 1019 cm-3) and defective surface region (within the top 150 Å from surface) rendered the as-activated Schottky diodes quasiohmic in their I-V characteristics. The leaky I-V characteristics, often reported in the literature, was likely to be originated from the surface layer, which gives rise to carrier tunneling across the Schottky barrier. This highly doped/defective surface region, however, can play an important role in ohmic contact formation on p-GaN.
Original language | English |
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Pages (from-to) | 292-296 |
Number of pages | 5 |
Journal | IEEE Transactions on Electron Devices |
Volume | 50 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2003 |
Keywords
- Doping
- Schottky barriers
- Surface
- Tunneling
- p-GaN