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

Abstract

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...

Progress in semiconductor diamond photodetectors and MEMS sensors

“…Especially, the MPCVD growth technique has been widely used nowadays for the growth of large-size SCD [12,13] and led to numerous applications of diamond as a semiconductor material. These applications include field-effect transistors and diodes for power electronics [14][15][16][17][18][19][20], microwave devices [21][22][23][24][25], deep-ultraviolet (DUV) light emitting diodes (LED) [26][27][28], DUV photodetectors [29,30], radiation detectors [31][32][33][34][35], microelectromechanical systems (MEMS) [36][37][38][39], and quantum sensors [40][41][42]. The utilization of diamond as a heat sink has also been attracting growing interesting in the application of high-power high-frequency communication, electrical power switch and others, in which the thermal dissipation is a problem [43][44][45][46][47].…”

Ultrathin Diamond Nanofilms—Development, Challenges, and Applications

“…[186] A better Q-factor of around 70 000 was obtained by Akgul et al for an NCD disk resonator. [187] A pivotal driving force for the generation, improvement, and investigation of these MEMS/NEMS resonators with high Q-factors and high frequencies is the potential application of these resonators as chemical and biological sensors, [188][189][190] and the fact that high Q-factors and high frequencies improve the sensitivity of the sensors. Notably, these high Q-factors were obtained with top-down synthesis strategies, yet recently, Q-factors of around 10 000 were obtained for a disk resonator made via bottom-up techniques, showing that this research area is still active.…”

Microwave diamond devices technology: Field‐effect transistors and modeling

“…Monocrystalline h‐BN is a two‐dimensional wide‐bandgap material with no dangling bonds, 20 which can greatly reduce the surface‐charged impurity scattering and achieve a high carrier mobility of 300 cm 2 V −1 s −1 for a carrier density of 5 × 10 12 cm −2 . To reduce power consumption, a normally off operation and low‐switching‐loss diamond metal‐insulator‐metal‐semiconductor field‐effect transistor (MIMS FET) was reported by Liao et al 21 in 2019 by combining the advantages of MOSFET and MESFET. The schematic of the MIMS FET structure is described in Figure 4.…”