Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state
Multichannel high electron mobility transistor (MC-HEMT) heterostructures are one of the choices for improved power performance of GaN HEMTs. By comparing the experimentally obtained two-dimensional electron gas (2DEG) concentration of unintentionally doped (UID) AlGaN/GaN MC-HEMTs with simulated 2D...
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| Format: | Journal Article |
| Language: | English |
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2023
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| Online Access: | https://hdl.handle.net/10356/171425 |
| _version_ | 1811695420280143872 |
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| author | Lingaparthi, R. Dharmarasu, Nethaji Radhakrishnan, K. Huo, Lili |
| author2 | School of Electrical and Electronic Engineering |
| author_facet | School of Electrical and Electronic Engineering Lingaparthi, R. Dharmarasu, Nethaji Radhakrishnan, K. Huo, Lili |
| author_sort | Lingaparthi, R. |
| collection | NTU |
| description | Multichannel high electron mobility transistor (MC-HEMT) heterostructures are one of the choices for improved power performance of GaN HEMTs. By comparing the experimentally obtained two-dimensional electron gas (2DEG) concentration of unintentionally doped (UID) AlGaN/GaN MC-HEMTs with simulated 2DEG concentration, we hypothesized that hole trap(s) exist at the buried GaN/AlGaN interfaces, which act as sources of 2DEG in UID MC-HEMT heterostructures. Furthermore, these hole traps stop the Fermi level from cutting the valence band at GaN/AlGaN interfaces, which in turn precludes the generation of parallel two-dimensional hole gas (2DHG) in the MC-HEMT. However, no experimental report is present as a proof for the existence of such a hole trap in MC-HEMT heterostructures. In this study, a capacitance-conductance method on single and dual channel HEMTs revealed traps with higher time constant of 19-28.7 μs exclusively for the dual channel HEMT heterostructure. These traps are observed at the buried GaN/AlGaN interface of the dual channel HEMT; hence, they are attributed to possible hole traps at this interface. By conducting systematic deep level transient spectroscopy measurements, the existence of hole traps is confirmed at the buried GaN/AlGaN interface with an activation energy of 717 meV and a capture cross section of 1.3 × 10−14 cm2. This experimental evidence of the existence of hole traps at the GaN channel/AlGaN interface further supports our claim that these hole traps act as the source of 2DEG in UID MC-HEMTs and that buried parallel 2DHG channels do not exist in MC-HEMTs. |
| first_indexed | 2024-10-01T07:23:11Z |
| format | Journal Article |
| id | ntu-10356/171425 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:23:11Z |
| publishDate | 2023 |
| record_format | dspace |
| spelling | ntu-10356/1714252023-10-27T15:40:44Z Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state Lingaparthi, R. Dharmarasu, Nethaji Radhakrishnan, K. Huo, Lili School of Electrical and Electronic Engineering Temasek Laboratories @ NTU Center for Micro/Nano-electronics (CMNE) UMI3288 CINTRA, (CNRS/NTU/THALES) Engineering::Electrical and electronic engineering Transistor Heterostructures Trap State Multichannel high electron mobility transistor (MC-HEMT) heterostructures are one of the choices for improved power performance of GaN HEMTs. By comparing the experimentally obtained two-dimensional electron gas (2DEG) concentration of unintentionally doped (UID) AlGaN/GaN MC-HEMTs with simulated 2DEG concentration, we hypothesized that hole trap(s) exist at the buried GaN/AlGaN interfaces, which act as sources of 2DEG in UID MC-HEMT heterostructures. Furthermore, these hole traps stop the Fermi level from cutting the valence band at GaN/AlGaN interfaces, which in turn precludes the generation of parallel two-dimensional hole gas (2DHG) in the MC-HEMT. However, no experimental report is present as a proof for the existence of such a hole trap in MC-HEMT heterostructures. In this study, a capacitance-conductance method on single and dual channel HEMTs revealed traps with higher time constant of 19-28.7 μs exclusively for the dual channel HEMT heterostructure. These traps are observed at the buried GaN/AlGaN interface of the dual channel HEMT; hence, they are attributed to possible hole traps at this interface. By conducting systematic deep level transient spectroscopy measurements, the existence of hole traps is confirmed at the buried GaN/AlGaN interface with an activation energy of 717 meV and a capture cross section of 1.3 × 10−14 cm2. This experimental evidence of the existence of hole traps at the GaN channel/AlGaN interface further supports our claim that these hole traps act as the source of 2DEG in UID MC-HEMTs and that buried parallel 2DHG channels do not exist in MC-HEMTs. Ministry of Education (MOE) Published version The authors gratefully acknowledge the funding support from the Ministry of Education, Singapore (Award No. RG128/22). 2023-10-24T06:46:25Z 2023-10-24T06:46:25Z 2023 Journal Article Lingaparthi, R., Dharmarasu, N., Radhakrishnan, K. & Huo, L. (2023). Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state. Applied Physics Letters, 123(9), 092105-1-092105-5. https://dx.doi.org/10.1063/5.0147392 0003-6951 https://hdl.handle.net/10356/171425 10.1063/5.0147392 2-s2.0-85170234221 9 123 092105-1 092105-5 en RG128/22 Applied Physics Letters © 2023 Author(s). Published under an exclusive license by AIP Publishing. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1063/5.0147392 application/pdf |
| spellingShingle | Engineering::Electrical and electronic engineering Transistor Heterostructures Trap State Lingaparthi, R. Dharmarasu, Nethaji Radhakrishnan, K. Huo, Lili Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title | Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title_full | Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title_fullStr | Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title_full_unstemmed | Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title_short | Source of two-dimensional electron gas in unintentionally doped AlGaN/GaN multichannel high-electron-mobility transistor heterostructures—experimental evidence of the hole trap state |
| title_sort | source of two dimensional electron gas in unintentionally doped algan gan multichannel high electron mobility transistor heterostructures experimental evidence of the hole trap state |
| topic | Engineering::Electrical and electronic engineering Transistor Heterostructures Trap State |
| url | https://hdl.handle.net/10356/171425 |
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