Normally off AlGaN/GaN HEMT on Si substrate with selectively dry-etched recessed gate and polarization-charge-compensation δ-doped GaN cap layer

Wakejima, Akio; Ando, Akihiro; Watanabe, Akihide; Inoue, Keita; Kubo, Toshiharu; Osada, Yoshihito; Kamimura, Ryuichiro; Egawa, Takashi

doi:10.7567/apex.8.026502

Cited by 25 publications

(17 citation statements)

References 30 publications

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“…[20,21] For 2D semiconductors, p-n junctions at the MOSFET level has not been achieved yet. The formation of recess structure at the gate can successfully lead to normally off operation for 2DEG at the AlGaN/GaN interface, [31] but not applicable to H-terminated diamond and low-dimensional semiconductors.In this work, we propose and demonstrate the device concept of metal-insulator-metal-semiconductor FET (MIMS-FET) based on a 2DHG channel to overcome the drawbacks of MOSFET and MESFET. [22] While for metal-semiconductor FETs (MES-FETs), there is an intrinsic problem of forward bias limitation.…”

mentioning

confidence: 99%

Energy‐Efficient Metal–Insulator–Metal‐Semiconductor Field‐Effect Transistors Based on 2D Carrier Gases

Liao

Sang

Shimaoka

et al. 2019

Adv Elect Materials

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tical applications due to the high input impedance, breakdown voltage, and integration ability. Tremendous efforts have been made to achieve low subthreshold swing (SS) MOSFETs on low-dimensional materials to overcome the thermal limit of 60 mV dec −1 in conventional CMOS technology. [8][9][10] On the other hand, growing attention has also been paid to the extreme semiconductors MOSFETs based on 2DHG and 2DEG for the applications in high-power, high-frequency, and high temperature electronics. [11][12][13] However, state-of-the-art conventional MOSFETs based on low-dimensional channels such as 2DHG or 2DEG always exhibit normally on (depletion mode) behavior and show uncertainty in threshold voltage. [8][9][10][11][12][13][14][15][16] Energy-efficient normally off (enhancement mode) FETs with low SS values and tunable threshold voltage are strongly in demand from the viewpoint of energy-saving, safety aspects, gate reliability, and electronic circuit simplicity. [17] Junction FET by using p-n junction or Schottky metal gate can achieve normally off operation. [18,19] Nevertheless, many wide-bandgap semiconductors suffer from"asymmetric doping" limitation. For example, n-type dopants with shallow energy levels in diamond and stable p-type doping in ZnO are notoriously difficult. [20,21] For 2D semiconductors, p-n junctions at the MOSFET level has not been achieved yet. These bottlenecks makes inversion-type enhancement-mode MOSFETs difficult, although initial results were reported. [22] While for metal-semiconductor FETs (MES-FETs), there is an intrinsic problem of forward bias limitation. Normally off MOSFETs were reported through channel structure modification, [23] defective gate oxides, [24,25] surface treatments, [26][27][28][29] and ion implantation. [30] However, in most of the cases, the principle is based on the generation of defects, which degrade the device performance as well as the controllability. The formation of recess structure at the gate can successfully lead to normally off operation for 2DEG at the AlGaN/GaN interface, [31] but not applicable to H-terminated diamond and low-dimensional semiconductors.In this work, we propose and demonstrate the device concept of metal-insulator-metal-semiconductor FET (MIMS-FET) based on a 2DHG channel to overcome the drawbacks of MOSFET and MESFET. We show that the MIMS-FET exhibits normally off operation, low subthreshold swing ≈76 mV dec −1 , high drain current, high on/off current ratio over 10 9 , and low gate leakage. These electrical properties are thermally stable up 2D electron and hole gases (2DEG or 2DHG) based on semiconductor surface/interface or 2D materials are promising for next-generation integrated circuits and high-frequency and -power electronics. To reduce power consumption, normally off operation and low-switching-loss metal-oxide fieldeffect transistors (MOSFETs) based on 2DEG or 2DHG are highly in demand. The present methods to achieve normally off MOSFETs have various shortcomings such as reduction in carrier mobility, sacrifice of dra...

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mentioning

confidence: 99%

Energy‐Efficient Metal–Insulator–Metal‐Semiconductor Field‐Effect Transistors Based on 2D Carrier Gases

Liao

Sang

Shimaoka

et al. 2019

Adv Elect Materials

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“…The 3C‐SiC/Si(111) pseudosubstrates for the subsequent GaN growth were prepared using a two‐step growth method developed by Nishino . First, a very thin SiC layer (3 nm) is realized by carbonization of the Si surface where only a carbon‐based precursor (C 2 H 4 ) is present in the reactor.…”

Section: Methodsmentioning

confidence: 99%

“…They employ a tri‐gate structure , where the gate is wrapped around narrow AlGaN/GaN bodies from three sides (from the top and from both perpendicular sidewalls), similar to the tri‐gate Si MOSFETs which currently enjoy increasing popularity. Other possibilities to fabricate E‐mode AlGaN/GaN HEMTs are ultrathin AlGaN barriers , gate recess , or fluorine plasma treatment . In this article, we report on the processing and characterization of D‐ and E‐mode tri‐gate HEMTs based on GaN/Al 0.2 Ga 0.8 N/AlN/GaN heterostructures grown on Si substrates using an ultrathin SiC transition layer.…”

Section: Introductionmentioning

confidence: 99%

Enhancement- and depletion-mode AlGaN/GaN HEMTs on 3C-SiC(111)/Si(111) pseudosubstrates

Jatal

Baumann

Jacobs

et al. 2017

Phys. Status Solidi A

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The realization of depletion-mode planar and both enhancement-and depletion-mode tri-gate high electron mobility transistors (HEMTs) based on Al 0.2 Ga 0.8 N/AlN/GaN heterostructures grown on silicon substrates using an ultrathin 3C-SiC transition layer is presented. This substrate configuration simplifies heterostructure growth compared to SiC and thick 3C-SiC substrates. The threshold voltage of the tri-gate devices strongly depends on the AlGaN/GaN body (fin) width. A transition from depletion-mode to enhancement-mode operation occurred at 110 nm body width for tri-gate devices without Si 3 N 4 passivation, and is expected to occur at 75 nm for devices with Si 3 N 4 passivation. Threshold voltages of À0.25/ 0.35 V were achieved at fin widths of 82/100 nm with/without Si 3 N 4 passivation, respectively, for the tri-gate HEMTs in comparison to À3.5 V for the planar HEMTs. Cutoff frequencies f T of 45 GHz and maximum frequencies of oscillation f max of 50 GHz have been measured for our best 100-nm tri-gate enhancement-mode HEMTs, while depletionmode planar HEMTs with the same gate length showed 110 GHz for both f T and f max . This demonstrates the applicability of the developed substrate configuration for high-performance device applications.

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“…High energy ion-bombardment would lead to surface roughness, material surface damages and low etching selectivity. Wakejima et al [61] reported that the reasonably low bias RF power can be used to get high selectivity and low surface damage. Moreover, chamber pressure also has an impact on the etching rate.…”

Section: Mesa Etchingmentioning

confidence: 99%

A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability

et al. 2018

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GaN based high electron mobility transistors (HEMTs) have demonstrated extraordinary features in the applications of high power and high frequency devices. In this paper, we review recent progress in AlGaN/GaN HEMTs, including the following sections. First, challenges in device fabrication and optimizations will be discussed. Then, the latest progress in device fabrication technologies will be presented. Finally, some promising device structures from simulation studies will be discussed.

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Normally off AlGaN/GaN HEMT on Si substrate with selectively dry-etched recessed gate and polarization-charge-compensation δ-doped GaN cap layer

Cited by 25 publications

References 30 publications

Energy‐Efficient Metal–Insulator–Metal‐Semiconductor Field‐Effect Transistors Based on 2D Carrier Gases

Energy‐Efficient Metal–Insulator–Metal‐Semiconductor Field‐Effect Transistors Based on 2D Carrier Gases

Enhancement- and depletion-mode AlGaN/GaN HEMTs on 3C-SiC(111)/Si(111) pseudosubstrates

A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability

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