Nanofabrications of T shape gates for high electron mobility transistors in microwaves and THz waves, a review

Zhu, Mingyao; Xie, Yuying; Shao, Jinhai; Chen, Yifang

doi:10.1016/j.mne.2021.100091

Cited by 11 publications

(3 citation statements)

References 105 publications

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“…T-gates, as mentioned previously, are unique in that they not only improve breakdown as a field-plate structure [59,62], but also improve RF results in thin-channel FETs by decreasing the L G while maintaining a large cross-section. This reduces the gate access resistance and decreases the electron transport time, but does not degrade the noise figure [138]. Various T-gate RF FET structures are shown in Figure 11a-e that incorporate recessed gates with SiO 2 FP dielectrics (Figure 11a [139]), air FP dielectrics with implanted channels (Figure 11b,c [94,140]), MESFET with Al 2 O 3 passivation (Figure 11d [66]), and SiO 2 gate dielectrics with SiN x passivation (Figure 11e [93]).…”

Section: T-gatesmentioning

confidence: 99%

Progress in Gallium Oxide Field-Effect Transistors for High-Power and RF Applications

Maimon,

2023

Materials

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Power electronics are becoming increasingly more important, as electrical energy constitutes 40% of the total primary energy usage in the USA and is expected to grow rapidly with the emergence of electric vehicles, renewable energy generation, and energy storage. New materials that are better suited for high-power applications are needed as the Si material limit is reached. Beta-phase gallium oxide (β-Ga2O3) is a promising ultra-wide-bandgap (UWBG) semiconductor for high-power and RF electronics due to its bandgap of 4.9 eV, large theoretical breakdown electric field of 8 MV cm−1, and Baliga figure of merit of 3300, 3–10 times larger than that of SiC and GaN. Moreover, β-Ga2O3 is the only WBG material that can be grown from melt, making large, high-quality, dopable substrates at low costs feasible. Significant efforts in the high-quality epitaxial growth of β-Ga2O3 and β-(AlxGa1−x)2O3 heterostructures has led to high-performance devices for high-power and RF applications. In this report, we provide a comprehensive summary of the progress in β-Ga2O3 field-effect transistors (FETs) including a variety of transistor designs, channel materials, ohmic contact formations and improvements, gate dielectrics, and fabrication processes. Additionally, novel structures proposed through simulations and not yet realized in β-Ga2O3 are presented. Main issues such as defect characterization methods and relevant material preparation, thermal studies and management, and the lack of p-type doping with investigated alternatives are also discussed. Finally, major strategies and outlooks for commercial use will be outlined.

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Section: T-gatesmentioning

confidence: 99%

Progress in Gallium Oxide Field-Effect Transistors for High-Power and RF Applications

Maimon,

2023

Materials

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“…Fabrication of a T-shaped narrow gate is one of the important key processes for ultra-high-frequency high-electron mobility transistors (HEMTs) [1]. Currently, the most widely used method for fabricating T-shaped gates in HEMTs is electron beam lithography (EBL).…”

Section: Introductionmentioning

confidence: 99%

Comparative study of the sidewall shape and proximity effect in bilayer electron beam resist systems

Nemec,

Vutova,

Bencurova

et al. 2024

J. Phys.: Conf. Ser.

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The experimental investigation and simulation of electron beam lithography (EBL) for bilayer and trilayer resist systems have been carried out. Important parameters of the EBL process, such as dissolution rate, resolution, absorbed energy, and resist profile in the investigated bilayer resist systems, have been studied and discussed. Various combinations of resist layers with positive electron resist have been proposed to examine the effects of lithographic process parameters on the resist profile. The results of this work are intended for use in multilayer resist systems to produce high-frequency electronics, where the fabrication of a T-shaped gate is one of the most crucial processes.

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“…Traditionally, researchers have relied on E-beam lithography systems to fabricate devices with small gate length (L g ). However, for large-scale production, the E-beam lithography process proves to be time-intensive [17][18][19][20] and cost-unfriendly. Hence, it's critical to develop more efficient and cost-effective methods with higher yield to meet industrial requirements.…”

mentioning

confidence: 99%

Spacer Side-wall Processed 0.15 μm GaN HEMT for Ka-band Application

Zhang,

Lv,

Ding

et al. 2024

ECS J. Solid State Sci. Technol.

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In this paper, we have effectively demonstrated 150 nm-gate-length AlGaN/GaN high electron mobility transistors (HEMTs) on 4-inch SiC substrate. The 150 nm gate-length was accomplished by utilizing traditional I-line stepper photolithography, together with a nitride spacer side-wall. This method offers superior processing efficiency compared to E-beam lithography with high wafer uniformity. The devices processed with this spacer side-wall aided method demonstrated comparable electrical performances as that of E-beam processed one with fT of 45 GHz, fMAX of 80 GHz, Pout of 31 dBm and PAE of 45% at 29 GHz, which can be imported to large scale manufacturing.

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Nanofabrications of T shape gates for high electron mobility transistors in microwaves and THz waves, a review

Cited by 11 publications

References 105 publications

Progress in Gallium Oxide Field-Effect Transistors for High-Power and RF Applications

Progress in Gallium Oxide Field-Effect Transistors for High-Power and RF Applications

Comparative study of the sidewall shape and proximity effect in bilayer electron beam resist systems

Spacer Side-wall Processed 0.15 μm GaN HEMT for Ka-band Application

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