Analytical Model for Two-Dimensional Electron Gas Charge Density in Recessed-Gate GaN High-Electron-Mobility Transistors

Sharbati, Samaneh; Gharibshahian, Iman; Ebel, Thomas; Orouji, Ali A.; Franke, Wulf-Toke

doi:10.1007/s11664-021-08842-7

Cited by 18 publications

(6 citation statements)

References 31 publications

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“…Figure 11 shows the simulated 2-DEG densities of the five different gate-recessed structures simulated under the zero-bias condition. The 2-DEG density was observed to decrease as the gate-recessed depth increased; the 2-DEG density as a function of AlGaN barrier thickness was consistent with the theoretical calculation reported in previous studies [ 37 , 38 , 39 ].…”

Section: Resultssupporting

confidence: 91%

Optimization of Gate-Head-Top/Bottom Lengths of AlGaN/GaN High-Electron-Mobility Transistors with a Gate-Recessed Structure for High-Power Operations: A Simulation Study

Kang,

Choi,

Kim

et al. 2023

Micromachines

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In this study, we propose an optimized AlGaN/GaN high-electron-mobility transistor (HEMT) with a considerably improved breakdown voltage. First, we matched the simulated data obtained from a basic T-gate HEMT with the measured data obtained from the fabricated device to ensure the reliability of the simulation. Thereafter, to improve the breakdown voltage, we suggested applying a gate-head extended structure. The gate-head-top and gate-head-bottom lengths of the basic T-gate HEMT were symmetrically extended by 0.2 μm steps up to 1.0 μm. The breakdown voltage of the 1.0 μm extended structure was 52% higher than that of the basic T-gate HEMT. However, the cutoff frequency (fT) and maximum frequency (fmax) degraded. To minimize the degradation of fT and fmax, we additionally introduced a gate-recessed structure to the 1.0 μm gate-head extended HEMT. The thickness of the 25 nm AlGaN barrier layer was thinned down to 13 nm in 3 nm steps, and the highest fT and fmax were obtained at a 6 nm recessed structure. The fT and fmax of the gate-recessed structure improved by 9% and 28%, respectively, with respect to those of the non-gate-recessed structure, and further improvement of the breakdown voltage by 35% was observed. Consequently, considering the trade-off relationship between the DC and RF characteristics, the 1.0 μm gate-head extended HEMT with the 6 nm gate-recessed structure was found to be the optimized AlGaN/GaN HEMT for high-power operations.

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Section: Resultssupporting

confidence: 91%

Optimization of Gate-Head-Top/Bottom Lengths of AlGaN/GaN High-Electron-Mobility Transistors with a Gate-Recessed Structure for High-Power Operations: A Simulation Study

Kang,

Choi,

Kim

et al. 2023

Micromachines

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“…The threshold voltage also decreases when tAlGaN is decreased. This is attributed to the reduction of conduction band offset (∆EC) or quantum well depth [37] as tAlGaN decreases. The transconductance, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Impact of AlGaN Barrier Thickness and Substrate Material on the Noise Characteristics of GaN HEMT

Jarndal

Arivazhagan

Almajali

et al. 2022

IEEE J. Electron Devices Soc.

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In this paper, the impact of AlGaN barrier thickness (tAlGaN) and substrate leakage on the noise conductance and noise figure in GaN High Electron Mobility Transistor (HEMT) is investigated. The investigation and analysis in this paper are targeting the Low Noise Amplifier (LNA) applications. The noise analysis is carried out using Technology Computer-Aided Design (TCAD) physical simulator. Initially, the DC, RF, and noise simulations are validated against measurements of a GaN device. AlGaN barrier thickness (tAlGaN) is varied and its impact on the minimum noise figure (NFmin) is analyzed. It is observed that the NFmin decreases with tAlGaN reduction at the typical bias conditions of LNA. This observation on the impact of tAlGaN on the NFmin follows Fukui's model, which states that the NFmin decreases with the increase in transconductance. In addition, the impact of the substrate material on noise performance is analyzed. The substrates used for the investigation are Silicon (Si) and Silicon Carbide (SiC). At 40 GHz, it is found that the noise conductance and the NFmin of GaN HEMT on SiC substrate is reduced by 13% and 12%, respectively, in comparison with GaN HEMT on Si substrate. This could be attributed to the lower gate-tosubstrate capacitance of the GaN HEMT on SiC substrate.

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“…𝜓 𝑖 may have an unlimited number of dependent solutions due to |𝐻 − 𝑙𝜆|𝜓 𝑖 = 0, as presented by R. M. Chu [32]. Now, the 2DEG, 𝑛 2𝐷 (𝑧) is provided by the equation (15).…”

Section: A Transport Features Of 2degmentioning

confidence: 99%

“…Furthermore, the Schottky and Ohmic contacts degrade at higher temperatures, which reflects the importance of temperature stability and reliability for HEMTs. An analytical model for 2DEG charge density and TCAD simulation for the buffer layer to increase the breakdown critical field has been studied in [15][16][17]. Therefore, it is vital to analyze how the 2DEG transport works at different temperatures because the transport characteristics of 2DEG significantly impact the device's performance.…”

Section: Introductionmentioning

confidence: 99%

Analytical Modeling of Depletion-Mode MOSHEMT Device for High- Temperature Applications

Islam,

Packeer Mohamed,

Ahmad

et al. 2024

IEEE Access

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An analytical model for depletion-mode MOSHEMTs for high-temperature applications is compared against the experimental GaN HEMT data of the AlGaN/GaN MOSHEMT for temperature dependence of 2DEG simulated at 75 o C and 125 o C. Both temperatures reduce the 2DEG density by 4 % in the GaN HEMT and 3 % in the AlGaN/GaN MOSHEMT. The cause of this diminishing effect is determined to be the decrease of the conduction band offset at high temperatures. Additionally, the device performance degrades at high temperatures due to the immature behaviour of GaN material when it operates at high-power dissipation with poor thermal conductivity. The simulated AlGaN/GaN MOSHEMT performance is comparatively improved compared to the experimental AlGaN/GaN HEMT devices. This improvement could be used to understand the nature of the 2DEG density vs the temperature, hence could enhance the experimental performance of the AlGaN/GaN MOSHEMT.

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Analytical Model for Two-Dimensional Electron Gas Charge Density in Recessed-Gate GaN High-Electron-Mobility Transistors

Cited by 18 publications

References 31 publications

Optimization of Gate-Head-Top/Bottom Lengths of AlGaN/GaN High-Electron-Mobility Transistors with a Gate-Recessed Structure for High-Power Operations: A Simulation Study

Optimization of Gate-Head-Top/Bottom Lengths of AlGaN/GaN High-Electron-Mobility Transistors with a Gate-Recessed Structure for High-Power Operations: A Simulation Study

Impact of AlGaN Barrier Thickness and Substrate Material on the Noise Characteristics of GaN HEMT

Analytical Modeling of Depletion-Mode MOSHEMT Device for High- Temperature Applications

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