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Buffer‐Less Gallium Nitride High Electron Mobility Heterostructures on Silicon
,
Martin Frentrup,
Alexander M. Hinz,
James W. Pomeroy,
Daniel Field,
David J. Wallis,
Martin Kuball,
Rachel A. Oliver
Advanced Materials, Volume: 37, Issue: 9
Swansea University Author:
Saptarsi Ghosh
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DOI (Published version): 10.1002/adma.202413127
Abstract
Thick metamorphic buffers are considered indispensable for III-V semiconductor heteroepitaxy on large lattice and thermal-expansion mismatched silicon substrates. However, III-nitride buffers in conventional GaN-on-Si high electron mobility transistors (HEMT) impose a substantial thermal resistance,...
| Published in: | Advanced Materials |
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| ISSN: | 0935-9648 1521-4095 |
| Published: |
Wiley
2025
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| Online Access: |
Check full text
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa71579 |
| Abstract: |
Thick metamorphic buffers are considered indispensable for III-V semiconductor heteroepitaxy on large lattice and thermal-expansion mismatched silicon substrates. However, III-nitride buffers in conventional GaN-on-Si high electron mobility transistors (HEMT) impose a substantial thermal resistance, deteriorating device efficiency and lifetime by throttling heat extraction. To circumvent this, a systematic methodology for the direct growth of GaN after the AlN nucleation layer on six-inch silicon substrates is demonstrated using metal-organic vapor phase epitaxy (MOVPE). Crucial growth-stress modulation to prevent epilayer cracking is achieved even without buffers, and threading dislocation densities comparable to those in buffered structures are realized. The buffer-less design yields a GaN-to-substrate thermal resistance of (11 ± 4) m2 K GW−1, an order of magnitude reduction over conventional GaN-on-Si and one of the lowest on any non-native substrate. As-grown AlGaN/AlN/GaN heterojunctions on this template show a high-quality 2D electron gas (2DEG) whose room-temperature Hall-effect mobility exceeds 2000 cm2 V−1 s−1, rivaling the best-reported values. As further validation, the low-temperature magnetoresistance of this 2DEG shows clear Shubnikov-de-Haas oscillations, a quantum lifetime > 0.180 ps, and tell-tale signatures of spin-splitting. These results could establish a new platform for III-nitrides, potentially enhancing the energy efficiency of power transistors and enabling fundamental investigations into electron dynamics in quasi-2D wide-bandgap systems. |
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| College: |
Faculty of Science and Engineering |
| Funders: |
Henry Royce Institute. Grant Number: EP/P024947/1;
Engineering and Physical Sciences Research Council. Grant Number: EP/N017927/1 |
| Issue: |
9 |