We report on the formation of highly reliable Ti/Al-based Ohmic contacts to N-polar n-GaN for vertical light-emitting diodes via laser-annealing. All as-deposited samples are Ohmic with specific contact resistances of 1.1 - 4.3 × 10-4 Ω cm2. After annealing at 250 °C, unlike the untreated sample, the laser-annealed samples remain Ohmic with specific contact resistances of 2.6-3.9 × 10-4 Ωcm 2. The laser-annealed samples remain electrically stable up to 60 min at 300 °C. Laser-annealing causes the formation of interfacial TiN/\beta -AlN phases with rock salt structure. Based on X-ray photoemission spectroscopy and scanning transmission electron microscopy results, possible Ohmic mechanisms are described.
- laser annealing
- light-emitting diodes (LEDs)
- semiconductor-metal interfaces
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials