We report on the formation of high-quality ohmic contacts to p-GaN (N a = 4 × 1017/cm3) for UV flip-chip light-emitting diodes (LEDs) using a tin-zinc oxide (TZO) interlayer. It is shown that the TZO (2.5 nm)/Ag (250 nm) contacts produce contact resistivity of 1.58 × 10-4 Ω cm2 and reflectance of 76% at 405 nm when annealed at 530°C. Near-UV LEDs made with the annealed TZO/Ag p-contacts give forward-bias voltage of 3.26 V at 20 mA, and higher output power than those with single Ag contacts. Based on transmission electron microscopy and electrical results, possible ohmic formation mechanisms are discussed.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Science(all)
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering