CUED Publications database

Substantiation of buried two dimensional hole gas (2DHG) existence in GaN-on-Si epitaxial heterostructure

Sun, J and Longobardi, G and Udrea, F and Zhu, C and Camuso, G and Yang, S and Garg, R and Imam, M and Charles, A (2017) Substantiation of buried two dimensional hole gas (2DHG) existence in GaN-on-Si epitaxial heterostructure. Applied Physics Letters, 110. ISSN 0003-6951

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Gallium Nitride on Silicon (GaN-on-Si) devices feature a relatively thick epi buffer layer to release the stress related to the lattice constant mismatch between GaN and Si. The buffer layer is formed by several AlGaN-based transition layers with different Al contents. This work addresses the fundamental question of whether two-dimensional hole gases (2DHGs) exist at those interfaces where the theory predicts a high concentration of a negative fixed charge as a consequence of the discontinuity in polarization between the layers. In this study, we demonstrate that the presence of such 2DHGs is consistent with the measured vertical Capacitance-Votage Profiling (CV) and Technology Caomputer-Aided Design (TCAD) simulation in the whole range of measurable frequencies (10 mHz–1 MHz). N-type compensating background donor included in the epi structure in the simulation deck proves to be crucial to explain the depletion region extension consistent with the CV experimental data. For the standard range of frequencies (1 kHz–1 MHz), there was no indication of the presence of 2DHGs. A set of ultra-low frequency (10 mHz–10 Hz) measurements performed were able to reveal the existence of 2DHGs. The outcome of these ultra-low frequency experiments was matched with TCAD simulations which validated our theory.

Item Type: Article
Divisions: Div B > Electronics, Power & Energy Conversion
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 18:57
Last Modified: 10 Apr 2021 00:46
DOI: 10.1063/1.4980140