Normally-off β-Ga2O3 MOSFET with an Epitaxial Drift Layer

Jang, Chan-Hee; Atmaca, G.; Cha, Ho-Young

doi:10.3390/mi13081185

Cited by 3 publications

(4 citation statements)

References 30 publications

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“…In the examined devices, with a recess depth of 110 nm placing the recess gate in the MOS channel, the device exhibited normally-on operation with a V TH of −4.9 V. Conversely, with a recess depth of 220 nm and the recess gate positioned in the inserted undoped buffer layer, it demonstrated normally-off operation with a V TH of +3.0 V. However, the maximum drain current in the case of normally-off operation was only 2.6 mA mm −1 [11], considerably lower than that reported by Chabak et al using a recessed-gate MOSFET [10]. In our previous study, we demonstrated a recessed-gate MOSFET with an epitaxial drift layer for improving the maximum drain current and R ON characteristics [12]. In the device concept, an epitaxial drift layer grown on an n-type low-doped body layer was employed, and the use of a lowdoped body layer under the MOS gate enabled the normally-off operation.…”

Section: Introductionmentioning

confidence: 63%

“…Instead of using a hetero-p-type material, several approaches, such as gate recess etching, can enable a normally-off operation [3][4][5]7]. A gate recess process partially removes the epitaxial channel under the gate, and it depletes electrons in the channel at V GS = 0 V with a positive threshold voltage (V TH ) [7,[10][11][12]. Several studies have reported different types of normally-off recessed-gate metal-oxidesemiconductor field-effect transistors (MOSFETs).…”

Section: Introductionmentioning

confidence: 99%

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Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier

Atmaca,

Cha

2024

Phys. Scr.

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This study demonstrates enhancement-mode recessed-gate β-Ga2O3 metal–oxide–semiconductor heterojunction field-effect transistors (MOSHFETs) with a combination of the MOS channel and a modulation-doped heterostructure to improve maximum drain current and on-resistance (RON). In this proposed device concept, modulation doping in the heterostructure back-barrier inserted into the MOS channel increases the electron density in the MOS channel while maintaining a normally-off operation. First, 2D simulations of enhancement-mode recessed-gate β-Ga2O3 metal–oxide–semiconductor field-effect transistors (MOSFETs) were performed in a Silvaco ATLAS TCAD environment to calibrate the transfer characteristics with the measured data of the investigated device reported previously. Second, using calibrated physical models and parameters, the transfer and transconductance characteristics, and output and off-state characteristics of the enhancement-mode recessed-gate β-Ga2O3 MOSHFETs were comprehensively investigated. The maximum drain current at VGS = 8 V and VDS = 10 V could be increased up to 32.6 mA/mm from 9.1 mA/mm with the MOSHFET in comparison with that of the recessed-gate MOSFET. The breakdown voltage increased considerably from 186 V to 226 V for the recessed-gate MOSHFET. The proposed device also showed a lower RON, which decreased from 354 Ω.mm to 214 Ω.mm owing to greater electron accumulation in the channel owing to the introduction of the modulation-doped heterostructure.

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Section: Introductionmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier

Atmaca,

Cha

2024

Phys. Scr.

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“…At high V GS and V DS , however, the drain current is nearly equal, indicating that the recess depth has little actual effect on the peak drain current. A slightly different trench FET design using body and epitaxial drift layers with different dopings, as well as recess through the entire drift layer, is shown in Figure 6c [117]. From I-V transfer curves with a drift layer doping of 3 × 10 17 cm −3 and varying body doping from 1 × 10 13 to 1 × 10 17 cm −3 , E-mode operation was only realizable for a body doping of 1 × 10 15 cm −3 or less, showing a larger current and more negative V th for higher doping concentrations.…”

Section: Trench/recessed-gate Fetsmentioning

confidence: 99%

“…Body-doping effects on E-/D-mode operation as well as a 2D crosssection of band bending through the body layer at low dopings. Reproduced from [117]. CC BY 4.0.…”

Section: Trench/recessed-gate Fetsmentioning

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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Scaled β-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz fMAX

Saha

Vaidya

Bhuiyan

et al. 2023

Applied Physics Letters

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This Letter reports a high performance β-Ga2O3 thin channel MOSFET with T gate and degenerately doped (n++) source/drain contacts regrown by metal organic chemical vapor deposition. Highly scaled T-gate with a gate length of 160–200 nm was fabricated to achieve enhanced RF performance and passivated with 200 nm silicon nitride. Peak drain current (ID,MAX) of 285 mA/mm and peak transconductance (gm) of 52 mS/mm were measured at 10 V drain bias with 23.5 Ω mm on resistance (RON). Metal/n++ contact resistance of 0.078 Ω mm was extracted from transfer length measurements. RON is possibly dominated by interface resistance between channel and highly doped n++ regrown layer. A gate-to-drain breakdown voltage of 192 V is measured for LGD = 355 nm resulting in average breakdown field (EAVG) of 5.4 MV/cm. This EAVG is the highest reported among all sub-micron gate length lateral FETs. Current gain cut off frequency (fT) of 11 GHz and record power gain cut off frequency (fMAX) of approximately 48 GHz were extracted from small signal measurements. fT is limited by DC-RF dispersion due to interface traps which needs further investigation. The fT·VBR product is 2.112 THz V for 192 V breakdown voltage. Device surpasses the switching figure of merit of Silicon and competitive with mature wide bandgap devices.

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Normally-off β-Ga2O3 MOSFET with an Epitaxial Drift Layer

Cited by 3 publications

References 30 publications

Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier

Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier

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

Scaled β-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz fMAX

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Normally-off β-Ga2O3 MOSFET with an Epitaxial Drift Layer

Cited by 3 publications

References 30 publications

Normally-off recessed gate β-Ga2O3 MOSHFETs with a modulation-doped heterostructure back-barrier

Normally-off recessed gate β-Ga2O3 MOSHFETs with a modulation-doped heterostructure back-barrier

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

Scaled β-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz fMAX

Contact Info

Product

Resources

About

Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier

Normally-off recessed gate β-Ga₂O₃ MOSHFETs with a modulation-doped heterostructure back-barrier