Boron-doped diamond (BDD) has attracted much attention as a promising electrode material especially for electrochemical sensing systems, because it excellent properties such wide potential window and low background current. It is known that the of BDD electrodes are very sensitive to surface termination whether hydrogen- or oxygen-terminated. Pretreating by cathodic reduction (CR) hydrogenate been widely used achieve high sensitivity. However, little about effects CR treatment conditions on...

To study the influence of crystal orientation on electrochemical properties boron-doped diamond (BDD), electrodes comprising (100) and (111) homoepitaxial single-crystal layers BDD were investigated these compared with a thin polycrystalline electrode. The samples similar amounts boron around 1020 cm–3 resistivity 6 × 10–3 Ω cm prepared. Evaluation reactivity each both H- O-terminated surfaces showed that was most reactive, whereas proved to be more reactive than ones for BDD. Moreover,...

Aqueous electrolytes have great potential to improve the safety and production costs of Li-ion batteries. Our recent materials exploration led discovery Li-salt dihydrate melt Li(TFSI)0.7(BETI)0.3·2H2O, which possesses an extremely wide window. To clarify detailed liquid structure electronic states this unique aqueous system, a first-principles molecular dynamics study has been conducted. We found that water molecules in hydrate exist as isolated monomers or clusters consisting only few (at...

Abstract We have theoretically investigated the effect of an interface trap charge (ITC) on Coulomb oscillation characteristics in a Si MOS-type quantum dot (Q-dot). found that ITC causes variation fundamental oscillation: peak position, height, and interval. clarified dependence each position is different from other because their physical origins. also discussed amount viewpoint operation Q-dots required computers (QCs). Mitigating large caused by will be critical issue for achieving...

Carbon-based materials are regarded as an environmentally benign alternative to the conventional metal electrode used in electrochemistry from viewpoint of sustainable chemistry. Among various carbon materials, boron-doped diamond (BDD) exhibits superior electrochemical properties. However, it is still uncertain how surface chemical species BDD influence performance, because difficulty characterizing species. Here, we have developed situ spectroscopic measurement systems on electrodes, i.e.,...

This study investigated changes in low-frequency noise sources associated with short-channel bulk metal-oxide-semiconductor field-effect transistors (MOSFETs) by analyzing random telegraph (RTN) from 300 K down to 3 K. The power spectral density (PSD) of the drain current, which exhibited RTN characteristics frequency domain, changed temperature. In addition, effect temperature on PSD was not monotonic such that peaks were generated at specific temperatures. A comparison between p-type and...

Abstract The tunnel field-effect transistor (TFET) is one of the candidates replacing conventional metal–oxide–semiconductor transistors to realize low-power-consumption large-scale integration (LSI). most significant issue in practical application TFETs concerns their low tunneling current. Si an indirect-gap material having a band-to-band probability and not favored for channel. However, new technology enhance current Si-TFETs utilizing isoelectronic trap (IET) was recently proposed. IET...

We have experimentally clarified the origin of low-frequency noise, which limits coherence-time in Si quantum bit (qubit), utilizing cryo-CMOS. At cryogenic temperature (2.5 K), significantly enhanced 1/f noise is observed MOSFETs, while it not seen at room temperature. Interface trap density dependence changing surface orientation, revealed that governed by carrier number fluctuation and we identified interface temperature, for first time. The present study demonstrates experiments using...

This study investigates the origin of low-frequency (LF) 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f$ </tex-math></inline-formula> noise in Si n-channel metal-oxide-semiconductor field-effect transistors (n-MOSFETs) under cryogenic operation. The fluctuation drain current increased with decreasing temperature, exhibiting LF more than two orders magnitude higher at 2.5 K compared that 300 K. As...

Abstract In this study, we propose technologies for the device structure, gate fabrication process, and back-bias-assisted operation of Si spin qubits to realize high robustness two-qubit SWAP against process variations. We performed quantum simulations MOS-type devices verified benefits these on fidelity. clarified that significantly improve variations achieve a 6 σ -yield with 99% fidelity, assuming size fluctuation International Roadmap Devices Systems (IRDS) target 2022. The proposed...

For the first time, we clarified low-frequency noise source of short-channel bulk MOSFETs at cryogenic temperature. We experimentally revealed that, with decreasing temperature, sources transition from inner-oxide traps to interface and then band-edge localized states that have energy levels within a few tenths meV conduction band-edge. This occurs because Fermi level shifts near band, resulting in charge responsible for being filled shallower contributing noise. Determining is critical step...

The electronic properties of isoelectronic impurity complexes in Si, such as Al+N and Mg+O, are studied by first-principles calculations. It is shown that cation anion atoms prefer to locate at the nearest-neighboring sites produce an electron-unoccupied state band gap Si. This made up 3s orbital N/O atoms, which hybridizes with 3p orbitals localized around atoms. chemical trend complex on changing type constituent atom also discussed.

Since a boron-doped diamond (BDD) exhibits excellent electrode properties such as wide potential window, low back-ground current, and high physical chemical durability, it has been studied an material for various electrochemical applications. The behavior of BDD depends on the surface termination, which can be easily converted by reactions. Fluorine termination attracted interest because unique hydrophobicity coefficient friction, also drastically change. However, so far, not elucidated why...

The stability and electronic structures of various isoelectronic cation+anion pairs in Si were studied by first-principles calculations. It was shown that the nearest-neighboring substitutional configuration is most stable structure for pairs, while B+N, Mg+O, Be+O preferentially occupy a single site owing to small atomic radii B, N, O atoms. We found only Al+N, Ga+N, In+N produce electron-unoccupied weakly localized states band gap Si, reflecting large negativity N also showed doping...

We experimentally performed temperature-dependent current‒voltage (I‒V) analysis of Si n-MOSFETs down to 15 mK, for the first time. found that saturated subthreshold swing (SS) at a few Kelvins decreased again in milli-Kelvin range proportion temperature, exhibiting SS 0.071 mV/dec mK. provided physical model explain behavior and threshold voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> ) milli‒Kelvin via calculation, thus...

We clarified the effect of band edge states on Coulomb-limiting electron mobility in Si n-MOSFETs operated at cryogenic temperatures, for first time, by employing various surface orientations to produce different oxide-Si interface states. The (100)-, (120)-, and (110)-oriented differed significantly below 100 K. This was found occur near temperature which Fermi level starts pass high-density localized charge-trap located conduction edge, inverting channel. An awareness role with regard...

In order to integrate a five-phase inverter system into the limited space of an in-wheel motor, high temperature low stray inductance SiC half-bridge power module with volume about 5 ml was designed, fabricated and tested. The in calculated by electromagnetic simulator confirmed measurements be 4.4 nH. Double-pulse switching tests were conducted at temperatures up 200°C. Thermal resistance, including that substrate, 0.153 °C/W. Fast capability accomplished external gate resistance 1 Ω.

To realize high-temperature operation of Si qubits, deep impurity levels with large confinement energy, which are hardly thermally excited, have been introduced into wafers. Group II Zn and group VI impurities S Se, known to form levels, were the substrates by ion implantation. These samples analyzed for concentration-depth profiles, energy level depths, absence defects. introduce thin channels such as 50-nm-thick Si, we found introduction conditions so that concentration depth profiles...

We developed an integrated device simulator for quantum bits (qubits) based on in-house technology computer-aided design (TCAD) simulator. The outputs transport and qubit operations simultaneously. present several technologies that were implemented a the first time: semi-classical hybrid calculation scheme potential, fictitious charge method capacitance, modified Ampere's equations magnetic field, multi-channel analysis transport.

Abstract We adopt a buried nanomagnet (BNM) technology on one-dimensional (1D) array of silicon spin qubits, and its availability was investigated using numerical simulations. The qubit is formed in the center Si fin lower lateral part qubits. placed near generates strong slanting magnetic field qubit, enabling X-gate operation approximately 15 times faster than conventional cases. Furthermore, formation BNM self-aligned process suppresses dimensional variation caused by variation, thereby...

Abstract This study experimentally investigated the effects of an additional high-pressure hydrogen annealing (HPHA) on cryogenic operation Si (110)-oriented n-MOSFETs. The HPHA induced improvements in subthreshold swing (SS), threshold voltage ( V th ), and ON current at temperatures. Further, we analyzed SS-drain curves using analytical model concluded that reduced density band-edge states. In addition, analysis temperature-dependent supported this conclusion. Furthermore, effective...

Abstract The study aimed to theoretically investigate the transfer characteristics of MOSFETs at cryogenic temperatures elucidate experimental conditions affecting accurate estimation drain-induced barrier lowering (DIBL) parameter. Our Technology Computer Aided Design (TCAD) simulation revealed that featuring an underlap between gate and source/drain edges experience a significant shift in threshold voltage ( V t ) low drain d region, which causes misestimation DIBL This change is due...

Abstract Transfer learning was examined to predict current-voltage (I-V) characteristics of MOSFETs at cryogenic temperatures. An experimental dataset obtained from approximately 800 silicon-on-insulator using an automated wafer prober pre-train a 3-hidden-layer neural network (NN) model. based on the NN model then conducted another small 2 bulk MOSFETs. The transfer predicted more realistic I-V and threshold voltages than control trained only dataset. This study demonstrates MOSFET...