Low Trapping Effects and High Electron Confinement in Short AlN/GaN-On-SiC HEMTs by Means of a Thin AlGaN Back Barrier

Harrouche, Kathia; Venkatachalam, Srisaran; Ben-Hammou, Lyes; Grandpierron, François; Okada, Étienne; Medjdoub, Farid

doi:10.3390/mi14020291

Cited by 8 publications

(12 citation statements)

References 35 publications

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“…As reported, for GaN technology, a L G /t barrier ratio > 15 effectively suppresses SCEs and ensures a near theoretical frequency response [7]. This could be further coupled with a higher current drive, such as in the case of novel barrier layer III -nitride materials including binary or ternary compounds (such as lattice-matched InAlN, AlN or ScAlN) that demonstrate higher sheet carrier densities for higher output power densities [1,2,[9][10][11]. These materials, as demonstrated by Ambacher et al [1,2,9], can exhibit a high two-dimensional electron gas (2DEG) density for thin barrier layers and give sufficient room for scaling the device geometry while maintaining an adequate aspect ratio (L G /t barrier ).…”

Section: Introductionmentioning

confidence: 82%

“…Several experimental studies have reported the suitability of an in situ SiN x cap layer for preventing the formation of meandering channels, which improves device reliability [10,15]. The in situ SiN x cap layer is used to passivate the surface to suppress the barrier relaxation and neutralize the surface state charge, resulting in a higher 2DEG density [10,11,[15][16][17]. While the concept of an in situ SiN x cap layer seems promising, the realization of in situ SiN x is challenging and demands careful optimization of growth techniques, as both the composition and thickness can affect long-term 2DEG stability [17].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the methodologies discussed above, backbarrier techniques have been used to improve the 2DEG confinement and limit buffer leakage. The back-barrier raises the conduction band edge for improved 2DEG confinement and leakage characteristics [3,6,11]. The back-barrier also helps in limiting both the vertical leakage current and the bulk punch-through effect for improved breakdown characteristics [4,[32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…The back-barrier also helps in limiting both the vertical leakage current and the bulk punch-through effect for improved breakdown characteristics [4,[32][33][34]. To this end, several back-barrier materials have been investigated, with AlGaN [11,34,35] and InGaN [36] being commonly employed. The crystal quality of an AlGaN barrier is inferior to a GaN buffer, which degrades channel mobility and exhibits a higher degree of dislocation density for a high Al (χ Al ) content [37].…”

Section: Introductionmentioning

confidence: 99%

“…An AlGaN back-barrier with a higher Al content is desirable for a higher band offset; however, this is at the cost of 2DEG density [37]. Despite the apparent high quality and comparatively higher mobility of InGaN back-barriers (which suffer from parasitic channel effects [37]), several works still rely on AlGaN backbarriers [11,[32][33][34][35] due to compound stability and better RF performance.…”

Section: Introductionmentioning

confidence: 99%

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Efficacy of back barrier engineered Π-gate InAlN/GaN high electron mobility transistors for high-power applications

Sehra

Anand

Saraswat

et al. 2023

J. Phys. D: Appl. Phys.

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This work investigates the thin barrier InAlN/GaN HEMTs for high power applications through TCAD simulations. To begin with, the TCAD simulations were first calibrated with the in – house fabricated InAlN HEMT sample for both DC and Pulsed characteristics. The thin barrier InAlN/GaN HEMTs shows a large leakage current through the gate electrode due to a high gate injection which severely degrades the breakdown characteristics of the device and thus acts as a bottleneck for high power applications. To improve the 2DEG confinement and to consequently reduce the bulk leakage, back – barrier technique is used. The resistive GaN buffer is replaced with AlGaN back – barrier which improves the breakdown characteristics at the cost of output power density. Thus, to scale up the output power density, and further optimize the breakdown characteristics, a Π – shaped Gate is introduced to limit the gate leakage current through the InAlN barrier by virtue of its improved hot electron reliability. Coupled with the AlGaN back – barrier, the Π – Gate significantly improves the breakdown characteristics for achieving high output power densities, albeit with minor trade – offs to the device gain. To elucidate the compatibility towards high power applications, all the device architectures are dynamically characterized by Pulsed IV simulations and the trap related dispersive effects are investigated. Amongst all, the Π – shaped Gate coupled with the AlGaN back – barrier outperforms the conventional architectures by exercising superior electrostatic control over the channel and exhibiting a high linearity for high power mm – Wave applications.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Efficacy of back barrier engineered Π-gate InAlN/GaN high electron mobility transistors for high-power applications

Sehra

Anand

Saraswat

et al. 2023

J. Phys. D: Appl. Phys.

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Role of AlGaN back-barrier in enhancing the robustness of ultra-thin AlN/GaN HEMT for mmWave applications

Said,

Harrouche,

Medjdoub

et al. 2023

Microelectronics Reliability

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Physical insight of thin AlGaN back barrier for millimeter-wave high voltage AlN/GaN on SiC HEMTs

Shanbhag,

Grandpierron,

Harrouche

et al. 2023

Applied Physics Letters

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In this work, physical mechanisms underlying carbon-doped buffer combined with an AlGaN back-barrier layer are investigated in state-of-the-art millimeter-wave AlN/GaN transistors. We have fabricated devices with and without the insertion of a thin AlGaN back-barrier layer with reduced carbon concentration to analyze the improvement resulting from this buffer architecture. More specifically, the impact of the Al mole fraction into the back-barrier, carbon doping in the buffer, and channel thickness on 100 nm gate length device performance has been studied. It appears that a 150 nm undoped GaN channel followed by a highly carbon-doped GaN buffer results in good electron confinement at the expense of a high current collapse. On the other hand, an Al mole fraction of 25% in the AlGaN back barrier layer coupled with a 150 nm undoped GaN channel provides excellent electron confinement, resulting not only in a low DIBL under high electric field but also low current collapse. Calibrated on experimental devices, TCAD simulations reveal that the electric field penetration inside the GaN buffer is prevented owing to a strong polarization from the back barrier when the Al-content is high enough. That is why, the electron confinement is superior for the 25% Al mole fraction in the back barrier along with reduced current collapse. As a result, careful engineering of the carbon concentration together with the undoped GaN channel thickness is crucial to achieve robust devices, which can, thus, deliver high device performance with superior voltage operation while using short gate lengths.

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Low Trapping Effects and High Electron Confinement in Short AlN/GaN-On-SiC HEMTs by Means of a Thin AlGaN Back Barrier

Cited by 8 publications

References 35 publications

Efficacy of back barrier engineered Π-gate InAlN/GaN high electron mobility transistors for high-power applications

Efficacy of back barrier engineered Π-gate InAlN/GaN high electron mobility transistors for high-power applications

Role of AlGaN back-barrier in enhancing the robustness of ultra-thin AlN/GaN HEMT for mmWave applications

Physical insight of thin AlGaN back barrier for millimeter-wave high voltage AlN/GaN on SiC HEMTs

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