Effect of reactant gas stoichiometry of in-situ SiNx passivation on structural properties of MOCVD AlGaN/GaN HEMTs

Siddique, Anwar; Ahmed, Raju; Anderson, Jonathan; Piner, Edwin L.

doi:10.1016/j.jcrysgro.2019.03.020

Cited by 9 publications

(23 citation statements)

References 22 publications

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“…The total 2DEG sheet charge density before diamond deposition is 1.04E13 cm –2 , whereas the sheet charge density after diamond deposition is 0.99E13 cm –2 , which represents a modest 4.5% reduction. These 2DEG sheet charge density values are very comparable and even higher than previously reported values for similar structures and growth conditions.…”

Section: Results and Discussionsupporting

confidence: 84%

“…Using the analytical approach reported by Siddique et al, 42 the piezoelectric and spontaneous polarization for the AlGaN barrier (P PE(Barrier) , P SP(Barrier) , respectively) and GaN buffer layer (P SP(GaN) ) have been calculated from the XRD determined parameters given in Table 2. A 3% change in the barrier layer biaxial strain state is observed before and after diamond growth.…”

Section: Resultsmentioning

confidence: 99%

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Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Siddique¹,

Ahmed²,

Anderson³

et al. 2019

ACS Appl. Electron. Mater.

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Integration of diamond and AlGaN/GaN highelectron mobility transistors (HEMTs) terminated with an in situ grown SiN x interface layer via metal organic chemical vapor deposition is investigated. The effect of diamond growth on the structure and interface properties of the HEMT is studied using high-resolution X-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, and scanning transmission electron microscopy (STEM). No structural or physical damage is observed to the HEMT device layers as a result of the hot filament chemical vapor deposition diamond fabrication process. The TEM cross section confirms the smooth and abrupt interface of in situ SiN x /AlGaN/GaN before and after the diamond growth, with no detectable carbon diffusion into the GaN buffer layer. However, selective degradation of the in situ SiN x dielectric adhesion layer was observed at the SiN x /diamond interface. Using time domain thermoreflectance (TDTR), the effective isotropic thermal conductivity of the diamond was determined to be 176 −35 +40 W/m•K. The effective thermal boundary resistance of the diamond/ GaN interface (including the SiN x and additional layers) was 52.8 −3.2 +5.1 m 2 •K/GW.

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Section: Results and Discussionsupporting

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Siddique¹,

Ahmed²,

Anderson³

et al. 2019

ACS Appl. Electron. Mater.

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“…As the thickness increases to 5 nm, however, the leakage current slightly increases. This is because the size of the V-shaped pits becomes large due to the incidental etching process described above [18][19][20][21][22][23], even though the evidence is not shown in AFM image in Fig. 3.…”

Section: Resultsmentioning

confidence: 93%

“…This is because the rough AlGaN surface becomes smooth during the slow growth of the SiCN cap layer with growth rate (5 nm/hour). However, the surface morphology of the structure with 10 nm-thick SiCN cap layer becomes poor with rms roughness of 1.0 nm, which is believed to be due to the etching process of the AlGaN surface under DTBSi/NH 3 /CBr 4 gas conditions for longer growth time at high temperatures of 1100 C [18][19][20][21][22][23]. The etching of the AlGaN surface and its effect on the device performance will be further discussed later.…”

Section: Resultsmentioning

confidence: 99%

Effect of In-Situ Silicon Carbon Nitride (SiCN) Cap Layer on Performances of AlGaN/GaN MISHFETs

Lee

2021

IEEE J. Electron Devices Soc.

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AlGaN/GaN metal insulator semiconductor heterostructure field effect transistors (MISHFETs) with different thickness of in-situ silicon carbon nitride (SiCN) cap layer were investigated. It was found that in-situ SiCN layer not only increases the two dimensional electron gas (2DEG) density, but also effectively passivates the surface of the AlGaN/GaN MISHFET. The fabricated device with 2 nm-thick SiCN cap layer exhibits superior device performances, such as larger maximum transconductance (gm) and higher on/off drain-current ratio (ION/IOFF) compared to those of the device without SiCN cap layer.

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“…An optimized process produces a continuous, amorphous, and conformal coating of the III-nitride surface. 13 Using operando photoelectron nanospectroscopy, Omika et al explained the role of SiN x in surface electron trapping. 14 reduces the surface-trapped electrons by about 10% indiscriminately across the surface, which leads to weakening of the local electrical field.…”

Section: Introductionmentioning

confidence: 99%

Improved Electrical Properties of AlGaN/GaN High-Electron-Mobility Transistors by In Situ Tailoring the SiN_x Passivation Layer

Siddique

Ahmed

Anderson

et al. 2021

ACS Appl. Mater. Interfaces

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In situ metal–organic chemical vapor deposition growth of SiN x passivation layers is reported on AlGaN/GaN high-electron-mobility transistors (HEMTs) without surface damage. A higher SiN x growth rate, when produced by higher SiH4 reactant gas flow, enables faster lateral coverage and coalescence of the initial SiN x islands, thereby suppressing SiH4-induced III-nitride etching. The effect of in situ SiN x passivation on the structural properties of AlGaN/GaN HEMTs has been evaluated using high-resolution X-ray diffraction. Electrical properties of the passivated HEMTs were evaluated by clover-leaf van der Pauw Hall measurements. The key findings include (a) a correlation of constituent gas chemistry with SiN x stoichiometry, (b) the degree of suppression of strain relaxation in the barrier layer that can be optimized through the SiN x stoichiometry, and (c) optimum strain relaxation by tailoring the SiN x passivation layer stoichiometry that can result in near-ideal AlGaN/AlN/GaN interfaces. The latter is expected to reduce the carrier scatterings and improve electron mobility. Under optimized conditions, low sheet resistance and high electron mobility are obtained. At 10 K, a sheet resistance of 33 Ω/sq and a mobility of 16,500 cm2/V-s are achieved. At 300 K, the sheet resistance is 336 Ω/sq and mobility is 2020 cm2/V-s with a sheet charge density of 0.78 × 1013 cm–2.

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Effect of reactant gas stoichiometry of in-situ SiNx passivation on structural properties of MOCVD AlGaN/GaN HEMTs

Cited by 9 publications

References 22 publications

Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Effect of In-Situ Silicon Carbon Nitride (SiCN) Cap Layer on Performances of AlGaN/GaN MISHFETs

Improved Electrical Properties of AlGaN/GaN High-Electron-Mobility Transistors by In Situ Tailoring the SiN_x Passivation Layer

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Effect of reactant gas stoichiometry of in-situ SiNx passivation on structural properties of MOCVD AlGaN/GaN HEMTs

Cited by 9 publications

References 22 publications

Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Effect of In-Situ Silicon Carbon Nitride (SiCN) Cap Layer on Performances of AlGaN/GaN MISHFETs

Improved Electrical Properties of AlGaN/GaN High-Electron-Mobility Transistors by In Situ Tailoring the SiNx Passivation Layer

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Product

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Improved Electrical Properties of AlGaN/GaN High-Electron-Mobility Transistors by In Situ Tailoring the SiN_x Passivation Layer