We report on the formation of high-quality ohmic contacts to p-type GaN (4 × 1017 cm-3) using Ni (5 nm)/Rh (120 nm) and Ni (5 nm)/Au (5 nm)/Rh (120 nm) schemes for use in flip-chip light-emitting diodes (LEDs). Both the Ni/Rh and Ni/Au/Rh contacts become ohmic with specific contact resistances of 10-5 to 10-6 Ω cm2, when annealed at 350°C for 2 min in air ambient. LEDs are fabricated using the Ni/Au/Rh and Ni/Au contact layers, which give a forward-bias voltage of 3.32 and 3.45 V at injection current of 20 mA, respectively. This indicates that the Rh-based contacts could be suitable for high power flip-chip LEDs. All rights reserved.
ASJC Scopus subject areas
- Materials Science(all)