Substantiation of buried two dimensional hole gas (2DHG) existence in GaN-on-Si epitaxial heterostructure
| Autor: | Florin Udrea, Jinming Sun, Reenu Garg, Shu Yang, Giorgia Longobardi, Alain Charles, Gianluca Camuso, Mohamed Imam, Congyong Zhu |
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| Přispěvatelé: | Longobardi, Giorgia [0000-0001-9994-851X], Udrea, Florin [0000-0002-7288-3370], Apollo - University of Cambridge Repository |
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Physics and Astronomy (miscellaneous) Silicon business.industry chemistry.chemical_element Gallium nitride Heterojunction 02 engineering and technology 5104 Condensed Matter Physics 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences Stress (mechanics) chemistry.chemical_compound Lattice constant chemistry Depletion region 0103 physical sciences Optoelectronics 0210 nano-technology business Polarization (electrochemistry) 51 Physical Sciences |
| Zdroj: | Applied Physics Letters. 110:163506 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.4980140 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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