Demonstration of GaN MIS diodes by using AlN and Ga 2O 3(Gd 2O 3) as dielectrics

Abstract

GaN MIS diodes were demonstrated utilizing AlN and Ga 2O 3(Gd 2O 3) as insulators. A 345 Å of AlN was grown on the MOCVD grown n-GaN in a MOMBE system using trimethylamine alane as Al precursor and nitrogen generated from a SVT RF N 2 plasma. For the Ga 2O 3(Gd 2O 3) growth, a multi-MBE chamber was used and a 195 Å oxide was E-beam evaporated from a single crystal source of Ga 5Gd 3O 12. The forward breakdown voltage of AlN and Ga 2O 3(Gd 2O 3) diodes are 5 and 6 V, respectively, which are significantly improved over ∼1.2 V from that of a Schottky contact. From the C–V measurements, both kinds of diodes showed good charge modulation from accumulation to depletion at different frequencies. The insulator/GaN interface roughness and the thickness of the insulator were measured with X-ray reflectivity.