GaN MISIM Diode with High-k Dielectrics of ZrO₂ and Al₂O₃ for UV Sensing

Abstract

We fabricated a GaN MISIM (metal-insulator-semiconductor-insulator-metal) UV photodiode using two high-k dielectrics of ZrO 2 and Al 2 O 3 . The fabricated UV photodiode using ZrO 2 showed better photo-electronic properties than that using Al 2 O 3 . The dark and photo-responsive current density ratios of the device with ZrO 2 and Al 2 O 3 were 250 and 196 at 10 V bias. Their UV/visible rejection ratios (UVRRs) were 1.65 × 10 2 and 1.34 × 10 2 for 365 nm wavelength at 1 V bias, respectively. The noise spectral density of the device with ZrO 2 was 1.3 × 10 2 A 2 /Hz for 10 Hz at 3 V bias which has lower noise value than that with Al 2 O 3 . The GaN MISIM UV photodiode with ZrO 2 has over 20 % improved photo-electronic properties and lower noise than that with Al 2 O 3 .