Schottky barrier heights, carrier density, and negative electron affinity of hydrogen-terminated diamond

Tsugawa, Kazuo; Noda, Hiroshi; Hirose, Kazuyuki; Kawarada, Hiroshi

doi:10.1103/physrevb.81.045303

Cited by 48 publications

(32 citation statements)

References 62 publications

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“…Interestingly, at 623 K, SS value is as low as 105 mV dec −1 , lower than the theoretical value of 120 mV dec −1 . [42] The Schottky metal depletes the holes of the 2DHG channel and contributes to the normally off operation of the FET. Detailed mechanism shall be investigated later.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…24 , 26 This indicates a very low density of surface states (<10 11 cm -2 ), which is a necessary condition for operation of metal-insulator-semiconductor (MIS) or metal oxide semiconductor (MOS) FET device architectures, shown schematically in Figure 2 a. Metals with high work function such as Au (5.1 eV) show low Schottky barrier heights, typically less than 0.2 eV 24,26 and are advantageous for the formation of ohmic contacts. In contrast, metals with low work function such as Al (4.3 eV) exhibit a Schottky barrier of nearly 1 eV.…”

Section: Field-eff Ect Transistor Devices On the Hydrogenterminated Dmentioning

confidence: 98%

Diamond surface conductivity: Properties, devices, and sensors

2014

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“…To enhance better performance of diamond electronic devices, an excellent ohmic contact between electrode metal layer and diamond is needed 9,19–24 . Up to now, many investigations of ohmic contact between metal and diamond have been reported, such as gold (Au), platinum (Pt) and palladium (Pd) on hydrogen-terminated single crystal diamond, all of which yield important role in diamond device development so far 9,25,26 . However, Au could peel off during fabrication process, which indicates quite poor adherence of Au on hydrogen-terminated single crystal diamond film 9 .…”

Section: Introductionmentioning

confidence: 99%

Ohmic contact between iridium film and hydrogen-terminated single crystal diamond

Wang

Chang

et al. 2017

Sci Rep

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Investigation of ohmic contact between iridium (Ir) film and hydrogen-terminated single crystal diamond has been carried out with annealing temperature from 300 to 600 °C in argon (Ar) and hydrogen ambient. Electrodes were deposited on hydrogen-terminated single crystal diamond by electron beam evaporation technique, and specific contact resistivity has been measured by transmission line model. The interface between Ir film and hydrogen-terminated single crystal diamond was characterized by transmission electron microscopy and energy dispersive X-ray spectroscopy. Theoretical calculation value of barrier height between Ir film and hydrogen-terminated single crystal diamond was around −1.1 eV. All results indicate that an excellent ohmic contact could be formed between Ir film and hydrogen-terminated single diamond.

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Schottky barrier heights, carrier density, and negative electron affinity of hydrogen-terminated diamond

Cited by 48 publications

References 62 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

Diamond surface conductivity: Properties, devices, and sensors

Ohmic contact between iridium film and hydrogen-terminated single crystal diamond

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