Demonstration of GaN MIS diodes by using AlN and Ga2O3(Gd2O3) as dielectrics

GaN MIS diodes were demonstrated utilizing AlN and Ga2O3(Gd2O3) as insulato rs. A 345 Angstrom of AlN was grown on the MOCVD grown n-GaN in a MOMBE sys tem using trimethylamine alane as Al precursor and nitrogen generated from a SVT RF N-2 plasma. For the Ga2O3(Gd2O3) growth, a multi-MBE chamber was u sed and a 195 Angstrom oxide was E-beam evaporated from a single crystal so urce of Ga5Gd3O12 The forward breakdown voltage of AIN and Ga2O3(Gd2O3) dio des are 5 and 6 V, respectively, which are significantly improved over simi lar to 1.2 V from that of a Schottky contact. From the C-V measurements, bo th kinds of diodes showed good charge modulation From accumulation to deple tion at different frequencies. The insulator/GaN interface roughness and th e thickness of the insulator were measured with X-ray reflectivity. (C) 199 8 Published by Elsevier Science Ltd. All rights reserved.