Band Alignments of Atomic Layer Deposited ZrO2 and HfO2 High-k Dielectrics with (-201) β-Ga2O3. (6th December 2016)

• Record Type: Journal Article
• Authors: Wheeler, Virginia D.; Shahin, David I.; Tadjer, Marko J.; Eddy, Charles R.
• Is Part Of: ECS journal of solid state science and technology. Volume 6:Number 2(2017)
• Page Start: Q3052
• Page End: Q3055
• Publication Date: 2016-12-06
• Subjects: atomic layer deposition -- band alignment -- ga2O3 -- HfO2 -- high-k dielectrics -- x-ray photoelectron spectroscopy -- ZrO2; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0131702jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : The energy band alignment between atomic layer deposited (ALD) high-k dielectrics of ZrO2 and HfO2 with n-type β-Ga2 O3 was evaluated using x-Ray photoelectron spectroscopy. The valence band offset was found to be −0.3 ± 0.04 eV and −0.5 ± 0.04 eV for ZrO2 and HfO2, respectively, which produced type II, staggered gap alignments for both dielectrics with conduction band offsets greater than 1 eV. Capacitance-voltage measurements were conducted on metal-oxide-semiconductor (MOS) diodes and used to extract the dielectric constants (ɛ) of both oxides. ZrO2 films had a nearly ideal ɛ of 24.7 (ɛ ∼ 25), while HfO2 exhibited a significantly lower ɛ of 14 (ɛ ∼ 25–30). These results, combined with the small hysteresis (≤0.09 eV) in the capacitance-voltage behavior for both films, is indicative of the high quality of these ALD oxides and their interface with the β-Ga2 O3 making them potential candidates as gate dielectrics in power devices based on this relatively new ultra-wide bandgap material.