Reflective and Low-Resistance Zn/Rh Contacts to p-Type GaN for Flip-Chip Light-Emitting Diodes

摘要

We report on the formation of high-quality ohmic contacts to p-type GaN (5 X 10~(17)/cm~3) using a Rh (100 nm) layer combined with a 3 nm thick Zn interlayer for high-power flip-chip light-emitting diodes (LEDs). The as-deposited sample produces a nonlinear behavior. However, the samples annealed at 430 and 530 deg C for 1 min in air become ohmic with a contact resistivity of ~10~(-3) OMEGA cm~2. Measurements show that the reflectivity of the samples annealed at 530 deg C is 73 percent at 460 nm. LEDs fabricated using the Zn/Rh contact layers give forward-bias voltages of 3.09-3.12 V at an injection current of 20 mA.