We have investigated Ni-Zn alloy(5 nm)/Pd(5 nm) metallization schemes for use in forming high-quality ohmic contacts to p-GaN (5 × 1017 cm-3). The as-deposited Ni-Zn alloy/Pd contact exhibits nonlinear current-voltage (I-V) characteristics. However, annealing the contacts at 530°C for 1 min in either air or N2 ambient improves I-V behaviour drastically. It is shown that the contacts produce specific contact resistance of 6.95 × 10-5 and 4.8 × 10-5 Ω cm2 when annealed in N2 and air ambient, respectively. It is further shown that multi-quantum-well light-emitting diodes fabricated with the annealed Ni-Zn alloy/Pd contact layers give a forward-bias voltage of 3.17 and 3.28 V at an injection current of 20 mA when annealed in air and N2 ambient, respectively.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry