Band Line-up Investigation of Atomic Layer Deposited TiAlO and GaAlO on GaN. (22nd July 2020)

• Record Type: Journal Article
• Authors: Das, Partha; Jones, Leanne A. H.; Gibbon, James T.; Dhanak, Vinod R.; Partida-Manzanera, Teresa; Roberts, Joseph W.; Potter, Richard; Chalker, Paul R.; Cho, Sung-Jin; Thayne, Iain G.; Mahapatra, Rajat; Mitrovic, Ivona Z.
• Is Part Of: ECS journal of solid state science and technology. Volume 9:Number 6(2020)
• Publication Date: 2020-07-22
• Subjects: GaN -- Dielectrics - High-k -- Atomic layer deposition -- X-ray photoelectron spectroscopy -- Band offsets -- Kraut method -- Metal insulator semiconductor capacitor; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2162-8777/aba4f4
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : A comprehensive study of the band alignments of Tix Al1−x Oy (with x = 9%, 16%, 25%, 36%, 100%) and Gax Al1−x Oy (x = 5%, 20%, 80% and 95%) fabricated using atomic layer deposition on GaN has been presented using X-ray photoelectron spectroscopy and variable angle spectroscopic ellipsometry. The permittivity, k, has been found to be enhanced from ∼10 for 9% Ti in Tix Al1−x Oy to 76 for TiO2, however TiO2 brings an unfavorable band alignment and a small conduction band offset (<0.1 eV) with GaN. The latter has been observed for all studied Tix Al1−x Oy films deposited on GaN. On the other hand, Gax Al1−x Oy films show a substantial increase of the band gap from 4.5 eV for Ga2 O3 to 5.5 eV for x = 20% Ga and 6.0 eV for x = 5% Ga. A strong suppression of leakage current in associated Gax Al1−x Oy -based metal insulator semiconductor capacitors has also been observed, showing promise for device applications.