Impact of the substrate and buffer design on the performance of GaN on Si power HEMTs

Borga, M.; Meneghini, Matteo; Stoffels, Steve; Hove, M. Van; Zhao, Ming; Li, X.; Decoutere, Stefaan; Zanoni, Enrico; Meneghesso, Gaudenzio

doi:10.1016/j.microrel.2018.06.036

Cited by 17 publications

(9 citation statements)

References 7 publications

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“…The slope of the current curves is altered and the increase of current is capped when the drain voltage reached 22 V. This is due to the formation of a depletion region under high drain voltages at the silicon substrate. The depleted regions limit the voltage in the epi-structure and restrict the leakage current [28,29]. During depletion of the buffer, the electric field across the buffer increases and the carriers left behind are generated or ionized, allowing the leakage current to recover and increase the breakdown.…”

Section: Resultsmentioning

confidence: 99%

Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Hieu¹,

Hsu²,

Chiang³

et al. 2022

Semicond. Sci. Technol.

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In this study, the effects of AlN/GaN superlattice (SL) thickness on performances of AlGaN/GaN high electron mobility transistor (HEMT) heterostructure grown by metal-organic chemical vapor deposition (MOCVD) on silicon is investigated. Stress in GaN is controlled by varying the total thickness of the AlN/GaN SL. Improved crystal quality and surface roughness accomplished with 2200 nm-thick AlN/GaN SL, leads to an increase in high electron mobility (1760 cm2/V·s) as well as two-dimensional electron gas (2DEG) concentration (1.04×1013 cm-2). AlGaN/GaN metal-insulator-semiconductor HEMT (MIS-HEMT) fabricated on the heterostructure with SL buffer layer exhibits a significant improvement in maximum saturation current of 1100±29 mA/mm at VGS = 0 V and a low on-resistance (RON) of 4.3±0.15 Ω·mm for the optimized AlN/GaN SL. The 2200 nm-thick AlN/GaN SL supports the growth of stress-free GaN heterostructure, which can reduce the insertion loss for sub-6 GHz RF applications. This GaN HEMT structure based on superlattice buffer layer is suitable for low-frequency RF power applications.

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Section: Resultsmentioning

confidence: 99%

Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Hieu¹,

Hsu²,

Chiang³

et al. 2022

Semicond. Sci. Technol.

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“…All these defect levels result in the decrease of output current when the HEMT switched to on‐state, so‐called current collapse (CC) phenomenon. [ 82,83 ] The electrons trapping and detrapping processes also lead to a V th hysteresis behavior, which is usually observed in the MIS‐HEMT devices due to the near‐surface traps on the gate dielectrics.…”

Section: Modified Buffer Structuresmentioning

confidence: 99%

Recent Advances in GaN‐Based Power HEMT Devices

Cheng

Wang

et al. 2021

Adv Elect Materials

116

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The ever‐increasing power density and operation frequency in electrical power conversion systems require the development of power devices that can outperform conventional Si‐based devices. Gallium nitride (GaN) has been regarded as the candidate for next‐generation power devices to improve the conversion efficiency in high‐power electric systems. GaN‐based high electron mobility transistors (HEMTs) with normally‐off operation is an important device structure for different application scenarios. In this review, an overview of a series of effective approaches to improve the performance of GaN‐based power HEMT devices is given. Modified epistructures are presented to suppress defects and current leakage, and low‐damage recess‐free processes are discussed in fabricating normally‐off HEMTs. Possible effects of dielectrics on a metal–insulator–semiconductor (MIS) structure are also intensively introduced. Metal/semiconductor contact engineering is investigated, and fabrication of Au‐free ohmic contact and graphene insertion layer to enhance the device performance is emphasized. Finally, the effects of field plates are studied through the use of simulated and fabricated devices.

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“…It is also related to traps created in the buffer layer because of the lattice mismatch between the Si substrate and the GaN layer. During high-voltage operation, because of the fringing electric field between drain and source (and gate) electrodes, 2DEG (2-dimensional electron gas) carriers are forced to move across the intrinsic GaN barriers and trapped by the C-dopants and material defects [9]. The channel resistance increase during the stress state and decrease during recovery can be modeled based on the emission, redistribution, and retrapping of holes within the carbon-doped buffer [10].…”

Section: Introductionmentioning

confidence: 99%

Deep Source Metal Trenches in GaN-On-Si HEMTs for Relieving Current Collapse

Yang

Lin

et al. 2021

IEEE J. Electron Devices Soc.

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The dynamic on-resistance increase during power switching is one of the challenges of GaN-based HEMTs (high-electron-mobility transistors) for power electronic applications. Both the surface traps and buffer traps reduce channel carriers, resulting in decreased operating current during power switching. In this work, we propose a source metal trench toward the buffer region to alleviate channel carriers' trapping in the buffer region. We compare the dynamic behaviors of the HEMTs with the source trench fabricated within and out of the mesa region. The results indicate less dynamic on-resistance increase at higher drain and gate stress voltages of the device with source trench in the mesa, as compared with the device with source trench fabricated away from mesa, or the one without a trench. We further develop physical models, including multiple current-conducting paths, reduction of buffer traps through source trench, and the re-distribution of the electric field profile, to explain the phenomenon.

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Impact of the substrate and buffer design on the performance of GaN on Si power HEMTs

Cited by 17 publications

References 7 publications

Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Recent Advances in GaN‐Based Power HEMT Devices

Deep Source Metal Trenches in GaN-On-Si HEMTs for Relieving Current Collapse

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