Optimum Carbon Concentration in GaN-on-Silicon for Breakdown Enhancement in AlGaN/GaN HEMTs

Remesh, N and Mohan, N and Raghavan, S and Muralidharan, R and Nath, DN (2020) Optimum Carbon Concentration in GaN-on-Silicon for Breakdown Enhancement in AlGaN/GaN HEMTs. In: IEEE Transactions on Electron Devices, 67 (6). pp. 2311-2317.

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Abstract

This article reports on the experimental and analytical determination of the optimum carbon concentration in GaN to achieve enhanced breakdown in AlGaN/GaN high-electron mobility transistors (HEMTs). The lateral breakdown voltage increases when carbon doping is increased from 3× 10¹⁸ to 1019 cm-3 beyond which it decreases, whereas there is no substantial enhancement in the vertical breakdown voltage with carbon doping. We invoke carrier statistics in a compensated semiconductor vis-à -vis the formation energy of carbon-occupying Ga (or N) vacancies to explain the observed buffer leakage. Temperature-dependent data indicate that the buffer leakage current is due to hopping transport, the activation energy of which yields the positions of the defect states within the bandgap. The increase in buffer leakage beyond optimum C concentration is attributed to the formation of shallow donor traps by carbon atoms occupying Ga vacancies (CGa). The observations correlated with the relative intensities of the defect-mediated peaks in the cathodoluminescence (CL) data of the samples. Based on our findings, a C doping beyond 1019 cm-3 is not recommended for GaN buffers in order to achieve high breakdown voltages. © 1963-2012 IEEE.

Item Type:	Journal Article
Publication:	IEEE Transactions on Electron Devices
Publisher:	Institute of Electrical and Electronics Engineers Inc
Additional Information:	Copy right for this article belongs to Institute of Electrical and Electronics Engineers Inc
Keywords:	Activation energy; Aluminum gallium nitride; Carbon; Defects; Electric breakdown; Gallium nitride; III-V semiconductors; Semiconductor doping; Silicon; Wide band gap semiconductors, Algan/gan high electron-mobility transistors; Analytical determination; Carbon concentrations; Carrier statistics; High breakdown voltage; Relative intensity; Temperature dependent; Vertical breakdown voltages, High electron mobility transistors
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	05 Nov 2020 06:06
Last Modified:	05 Nov 2020 06:06
URI:	http://eprints.iisc.ac.in/id/eprint/65854

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