Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics



Roberts, Joseph, Chalker, Paul ORCID: 0000-0002-2295-6332, Lee, Kean Boon, Houston, Peter, Cho, S Jin, Thayne, Iain, Guiney, Iver, Wallis, David and Humphreys, Colin
(2016) Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics. Applied Physics Letters, 108 (7).

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Abstract

We report the modification and control of threshold voltage in enhancement and depletion mode AlGaN/GaN metal insulator-semiconductor heterostructure field effect transistors through the use of in-situ fluorine doping of atomic layer deposition Al2O3. Uniform distribution of F ions throughout the oxide thickness are achievable, with a doping level of up to 5.5x1019cm-3 as quantified by secondary ion mass spectrometry. This fluorine doping level reduces capacitive hysteretic effects when exploited in GaN metal-oxide-semiconductor capacitors. The fluorine doping and forming gas anneal also induces an average positive threshold voltage shift of between 0.75 and 1.36V in both enhancement mode and depletion mode GaN-based transistors compared with the undoped gate oxide via a reduction of positive fixed charge in the gate oxide from +4.67x1012 cm-2 to -6.60x1012 cm-2. The application of this process in GaN based power transistors advances the realisation of normally off, high power, high speed devices.

Item Type: Article
Subjects: Q Science > QC Physics
Q Science > QD Chemistry
Depositing User: Symplectic Admin
Date Deposited: 04 Mar 2016 08:54
Last Modified: 18 Jan 2021 12:10
DOI: 10.1063/1.4942093
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/2053524