Enhancement of two‐dimensional electron gases in AlGaN‐channel high‐electron‐mobility transistors with AlN barrier layers

Hashimoto, Shinji; Akita, Katsushi; Yamamoto, Yoshiyuki; Ueno, Masaki; Nakamura, Toshio; Takeda, Kenta; Iwaya, Motoaki; Honda, Yoshio; Amano, Hiroshi

doi:10.1002/pssa.201100379

Cited by 17 publications

(23 citation statements)

References 14 publications

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“…For a barrier thickness of 25 nm, the sheet charge density reported is 2.6407 × 10 13 /cm 2 . This result is consistent with experimentally reported carrier density of 2.8 × 10 13 /cm 2 [12]. Constant x interpolation is assumed from the experimental literature.…”

Section: Resultssupporting

confidence: 91%

“…This carrier sheet charge density is well matched with experimentally reported data. According to these results, AlN is partially strain-relaxed with the AlGaN channel, using the AlN buffer region [12]. A constant strain relaxation of 0.45 is included here.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 6. Sheet charge density versus barrier thickness for a constant x = 0.51 as calculated from the experimental literature[12]. A constant strain relaxation of 0.5 is taken into account here.…”

mentioning

confidence: 99%

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Relaxation rate and polarization charge density model for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN heterostructures

Sivarajan¹,

Korah²,

Ganamani³

2017

Turk J Elec Eng & Comp Sci

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This work describes the strain-relaxation-dependent carrier concentration ( ns) profile model using spontaneous and piezoelectric polarization for AlN/Al x Ga 1−x N/AlN HEMTs in all mole fraction ( x) interpolations. As x varies, the Aluminum Gallium Nitride (AlGaN) channel shows strain relaxation with the Aluminum Nitride (AlN) barrier. The degree of relaxation is modeled from AlN to GaN regions in the channel. It shows that the AlN barrier and buffer relaxation and strain recovery occurs due to the gradual crystal quality degradation from barrier/buffer to the channel interface. These combination devices show less drain current degradation with temperature variation from 300 K to 573 K. This model shows a good agreement with experimental data with a carrier density of ns = 2.8 × 10 13 /cm 2 .

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

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Relaxation rate and polarization charge density model for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN heterostructures

Sivarajan¹,

Korah²,

Ganamani³

2017

Turk J Elec Eng & Comp Sci

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“…Here we take this to be a constant value of 10 13 cm −2 over the entire composition range, consistent with experimental reports on Al-rich AlGaN/AlGaN heterostructures. 4,5,7,9 Other authors have taken the approach that n s is proportional to E C , 18 which eliminates n s from the LFOM and makes it proportional to E C 3 rather than E C 2 . Thus, in such a situation the LFOM has the same dependence on critical field as the UFOM (UFOM = εμE C 3 /4 where ε is the dielectric constant of the semiconductor (F/cm) and μ is the bulk mobility).…”

Section: Derivation Of the Lfommentioning

confidence: 99%

Analysis of 2D Transport and Performance Characteristics for Lateral Power Devices Based on AlGaN Alloys

Coltrin

Baca

Kaplar

2017

ECS J. Solid State Sci. Technol.

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Predicted lateral power device performance as a function of alloy composition is characterized by a standard lateral device figure-ofmerit (LFOM) that depends on mobility, critical electric field, and sheet carrier density. The paper presents calculations of AlGaN electron mobility in lateral devices such as HEMTs across the entire alloy composition range. Alloy scattering and optical polar phonon scattering are the dominant mechanisms limiting carrier mobility. Due to the significant degradation of mobility from alloy scattering, at room temperature Al fractions greater than about 85% are required for improved LFOM relative to GaN using a conservative sheet charge density of 1 × 10 13 cm −2 . However, at higher temperatures at which AlGaN power devices are anticipated to operate, this "breakeven" composition decreases to about 65% at 500 K, for example. For high-frequency applications, the Johnson figure-of-merit (JFOM) is the relevant metric to compare potential device performance across materials platforms. At room temperature, the JFOM for AlGaN alloys is predicted to surpass that of GaN for Al fractions greater than about 40%.

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“…The alloy of AlN and GaN and their alloy (AlxGa1-xN) have been intensively studied for decades [1][2][3][4][5][6] and they are very important materials for many applications in optoelectronic and power-electronic devices such as visible and ultraviolet light-emitting diodes, high electron mobility, solar cell, high-power electronic devices, field-effect transistor and high-speed electronic devices operating at high temperature and environments, etc. [7][8][9][10][11][12][13][14][15][16][17] AlxGa1-xN epitaxial layers are used for carrier confinement as electron blocking or barrier layers normally in laser and quantum-well ultraviolet light emitting diodes. [18][19][20] But there are a few publications on the properties of the AlxGa1-xN alloy and most of these papers are studied on the characteristics of AlxGa1-xN/GaN heterostructures having low Al composition values.…”

Section: Introductionmentioning

confidence: 99%

EFFECT OF AlN LAYERS ON THE AlxGa1-xN/GaN GROWN ON SAPPHIRE SUBSTRATES

Bun¹

2019

Preprint

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The effect of a thin AlN layer inserted between AlxGa1-xN/GaN heterostructures grown on sapphire substrates was investigated for possible application in opto-electronic and power electronic devices. The heterostructures with two different Al compositions (0.35 and 0.49) were applied to study. After growing a thin AlN interlayer (~10nm) on the buffer GaN/AlN/sapphire substrate, then a thick AlxGa1-xN/GaN heterostructure were grown and investigated the Al mole fractions. Low rocking curves were also achieved with 0.35 and 0.48 for the 0.3 and 0.49 Al compositions, respectively. The experimental results show that with an increasing of Al composition, the crystallinity is also improved with lower surface roughness. The AlxGa1-xN/GaN heterostructures with 0.35 and 0.49 Al compositions were also investigated the electrical characteristics to confirm that they are suitable for development in optoelectronic and power electronic devices.

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Enhancement of two‐dimensional electron gases in AlGaN‐channel high‐electron‐mobility transistors with AlN barrier layers

Cited by 17 publications

References 14 publications

Relaxation rate and polarization charge density model for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN heterostructures

Relaxation rate and polarization charge density model for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN heterostructures

Analysis of 2D Transport and Performance Characteristics for Lateral Power Devices Based on AlGaN Alloys

EFFECT OF AlN LAYERS ON THE AlxGa1-xN/GaN GROWN ON SAPPHIRE SUBSTRATES

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