We have investigated Ag (2.5 nm)/TiNx (50 nm)/Al (200 nm) contacts for use in GaN-based flip-chip light emitting diodes (LEDs). The Ag/TiNx/Al contact becomes ohmic with specific contact resistance of 4.4 × 10-3 Ω cm2 when annealed at 430°C for 1 min in nitrogen ambient. It is shown that the continuous Ag interlayer is broken into Ag nanodots when annealed. It is also shown that the TiNx barrier layer effectively hampers the indiffusion of Al toward GaN. Blue LEDs are fabricated using the annealed Ag/TiNx/Al contacts and are compared with those made with the annealed Ni/Au/Al contacts.
ASJC Scopus subject areas
- Materials Science(all)