Oxidized Si terminated diamond and its MOSFET operation with SiO2 gate insulator

Fei, Wenxi; Bi, Te; Iwataki, Masayuki; Imanishi, Shoichiro; Kawarada, Hiroshi

doi:10.1063/1.5143982

Cited by 40 publications

(15 citation statements)

References 34 publications

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“…Note that the reported D it -μ FE results of other diamond MOSFETs with different surface terminations are also inserted in Fig. 4c [21,42,43]. We can see that the μ FE and D it are inversely correlated.…”

Section: Inversion-type P-channel Mosfets On Homoepitaxial Diamond Substratesmentioning

confidence: 76%

Inversion-type p-channel diamond MOSFET issues

Zhang

Matsumoto

Yamasaki

et al. 2021

Journal of Materials Research

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This article reviews the state of the art in inversion-type p-channel diamond MOSFETs. We successfully developed the world’s first inversion-channel homoepitaxial and heteroepitaxial diamond MOSFETs. We investigated the dependence of phosphorus concentration (NP) of the n-type body on field-effect mobility (μFE) and interface state density (Dit) for the inversion channel homoepitaxial diamond MOSFETs. With regard to the electrical properties of both the homoepitaxial and heteroepitaxial diamond MOSFETs, they suffer from low μFE and one main reason is high Dit. To improve the interface quality, we proposed a novel technique to form OH-termination by using H-diamond followed by wet annealing, instead of the previous OH-termination formed on O-diamond. We made precise interface characterization for diamond MOS capacitors by using the high-low C–V method and the conductance method, providing further insights into the trap properties at Al2O3/diamond interface, which would be beneficial for performance enhancement of the inversion-type p-channel diamond MOSFETs. Graphic abstract

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Section: Inversion-type P-channel Mosfets On Homoepitaxial Diamond Substratesmentioning

confidence: 76%

Inversion-type p-channel diamond MOSFET issues

Zhang

Matsumoto

Yamasaki

et al. 2021

Journal of Materials Research

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“…The MOSFET device with a full SiO 2 layer exhibits the normally-off operation achieved at V th = -2.7 V threshold voltage as shown in Fig. 7 (a) 18 . The second MOSFET device uses a partial SiO 2 layer and the obtained experimental results correspond to the simulation work that confirmed normally-off operation using a positive surface charge model instead of SiO 2 .…”

Section: Gatementioning

confidence: 95%

“…In addition, Liu et al 17 confirmed the normally-off device operation using HfO 2 -gate MOSFETs. Fei et al 18 fabricated the two kinds of diamond metal oxide semiconductor field effect transistors (MOSFETs) electronic device, with a C-Si diamond channel (SiO 2 ). In the study, there are undoped and heavily boron-doped in contact area (source/drain), and both of the MOSFET devices exhibited normally-off FET characteristics (enhancement mode).…”

mentioning

confidence: 99%

An Enhanced Two-Dimensional Hole Gas (2DHG) C-H Diamond with Positive Surface Charge Model for Advanced Normally-Off MOSFET Devices

Alhasani¹,

Yabe²,

Iyama³

et al. 2020

Preprint

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Though the complementary power field effect transistore (FETs), e.g., metal-oxide-semiconductor-FETs (MOSFETs) based on wide badgap materials, enable low switching losses and on-resistance, p-channel FETs are not feasible in any wide bandgap material other than diamond. In this paper, we propose the first work to investigate the impact of fixed positive surface charge density on achieving normally-off and control threshold voltage operation obtained on p-channel two-dimensional hole gas (2DHG) hydrogen-terminated diamond (C-H) FET using deep nitrogen doping in the diamond substrate. In general, a p-channel diamond C-H MOSFET demonstrates normally-on operation, but the normally-off operation is also a critical requierment of the feasible electronic power devices in terms of safety operation. The evaluation results of the characteristic of the C-H MOSFET capacitor with the two demonstrated charge sheet models using the two-dimensional Silvaco Atlas TCAD show that the fixed-Fermi level is a function of capacitance-voltage with an activation energy of 1.7 eV (donor level) at the H-diamond surface close to minimum conduction band. The maximum current density with a positive surface charge model and a nitrogen-doped layer of the Al2O3/H-diamond device is -52 mA/mm at a gate-source voltage of -42 V. Also, the gate threshold voltage is relatively high at Vth= -3 V, i.e., the positive surface charge model can achieve the normally-off operation. Moreover, we demonstrate that the obtained results correspond to the experimental work with the SiO2 layer located below the gate in C-H diamond/Al2O3 surface.

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“…In addition, Liu et al 17 confirmed the normally-off device operation using HfO 2 -gate MOSFETs. Fei et al 18 fabricated the two kinds of diamond MOSFETs electronic device, with an oxidized Si terminated (C–Si) diamond channel. In the study, there are undoped and heavily boron-doped in the contact area (source/drain), and both of the MOSFET devices exhibited normally-off FET characteristics.…”

Section: Introductionmentioning

confidence: 99%

An enhanced two-dimensional hole gas (2DHG) C–H diamond with positive surface charge model for advanced normally-off MOSFET devices

Alhasani

Yabe

Iyama

et al. 2022

Sci Rep

Self Cite

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Though the complementary power field effect transistors (FETs), e.g., metal–oxide–semiconductor-FETs (MOSFETs) based on wide bandgap materials, enable low switching losses and on-resistance, p-channel FETs are not feasible in any wide bandgap material other than diamond. In this paper, we propose the first work to investigate the impact of fixed positive surface charge density on achieving normally-off and controlling threshold voltage operation obtained on p-channel two-dimensional hole gas (2DHG) hydrogen-terminated (C-H) diamond FET using nitrogen doping in the diamond substrate. In general, a p-channel diamond MOSFET demonstrates the normally-on operation, but the normally-off operation is also a critical requirement of the feasible electronic power devices in terms of safety operation. The characteristics of the C–H diamond MOSFET have been analyzed with the two demonstrated charge sheet models using the two-dimensional Silvaco Atlas TCAD. It shows that the fixed-Fermi level in the bulk diamond is 1.7 eV (donor level) from the conduction band minimum. However, the upward band bending has been obtained at Al2O3/SiO2/C-H diamond interface indicating the presence of inversion layer without gate voltage. The fixed negative charge model exhibits a strong inversion layer for normally-on FET operation, while the fixed positive charge model shows a weak inversion for normally-off operation. The maximum current density of a fixed positive interface charge model of the Al2O3/C-H diamond device is − 290 mA/mm, which corresponds to that of expermental result of Al2O3/SiO2/C-H diamond − 305 mA/mm at a gate-source voltage of − 40 V. Also, the threshold voltage Vth is relatively high at Vth = − 3.5 V, i.e., the positive charge model can reproduce the normally-off operation. Moreover, we also demonstrate that the Vth and transconductance gm correspond to those of the experimental work.

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Oxidized Si terminated diamond and its MOSFET operation with SiO2 gate insulator

Cited by 40 publications

References 34 publications

Inversion-type p-channel diamond MOSFET issues

Inversion-type p-channel diamond MOSFET issues

An Enhanced Two-Dimensional Hole Gas (2DHG) C-H Diamond with Positive Surface Charge Model for Advanced Normally-Off MOSFET Devices

An enhanced two-dimensional hole gas (2DHG) C–H diamond with positive surface charge model for advanced normally-off MOSFET devices

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