Characterizations of Al2O3 gate dielectric deposited on n‐GaN by plasma‐assisted atomic layer deposition

Abstract

AbstractThis paper briefly reviews the characterizations of Al2O3 gate dielectric deposited by plasma‐assisted atomic layer deposition (PA‐ALD) on n‐GaN. We report on insulating and physical properties of PA‐ALD Al2O3 film from I‐V characteristics of metal‐insulator‐semiconductor (MIS) diodes and analysis of X‐ray photoelectron spectroscopy (XPS), respectively. Compared to Al2O3 film deposited by thermal ALD method, the PA‐ALD Al2O3 film exhibited higher breakdown field and several orders of magnitude lower leakage current density. Analysis of the current conduction mechanism reveals that the gate leakage current of PA‐ALD Al2O3/n‐GaN MIS diode consisted of Schottky emission (SE) and Fowler‐Nordheim tunneling (FNT). In contrast, it is suggested that trap‐assisted tunneling (TAT) mechanism was dominant in the gate leakage of T‐ALD Al2O3 sample at the middle field range. From the XPS analysis, the band gap of PA‐ALD Al2O3 was estimated about 6.7 eV. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)