We studied the effect of post deposition annealing (PDA) on electrical properties of gallium oxide (GaOx) /silicon (Si) structure fabricated by mist chemical vapor deposition (CVD). The effective fixed charge density (Qeff) and the interfacial trap density (Dit) were characterized by a high-low frequency capacitance-Voltage (C-V) technique. The chemical-bonding states of the GaOx/Si structures were determined by the XPS spectra. As a result, although the negative Qeff was almost constant regardless of the PDA conditions, the Dit was decreased in H2 atmosphere. It was considered that the decreased in Dit is to contribute to the decrease in the dangling bonds on the Si surface form the results of the XPS spectra.
Neuromorphic computing is a broad, interdisciplinary field that spans across all levels of the compute stack, from applications and algorithms to devices and materials. When designing a new computing system from the ground up, co-design is key. Here, we discuss different types of co-design for neuromorphic systems, and we advocate specifically for omnidirectional co-design. Finally, we discuss recommendations for performing omnidirectional co-design, based on our own experience in the realm of neuromorphic computing.
Polarized light observation is one of the promising methods for the non-destructive characterization of semiconductor wafers for power devices. We have visualized the distribution of defects in SiC wafers by birefringence imaging.
Insertion of partial monolayers of oxygen atoms into Si lattice leads to modification of formation enthalpy of various dopants and point defects, enabling remote control of doping profiles away from the inserted film. 18 O isotope tracer revealed exchange of oxygen atoms between oxygen-insertion layers and gate oxide. This finding likely accounts for 35% improvement of surface roughness scattering rate of inversion electrons as well as 6x improvement of charge-to-breakdown of thin gate dielectrics experimentally observed. Impact of the OI(oxygen inserted)-Si channel is greater for HKMG(high-k metal gate) stack due to modification of interface charge properties.
the frequency response of Polyimide-Supported AlScN thin Films based surface acoustic wave (SAW) delay line is investigated. The elastic, dielectric and piezoelectric coefficients of AlScN alloys in the range of Scandium concentration x = 0, 0.125, 0.25 and 0.375 are obtained. It is found that the scandium content has a major impact on the electro-acoustic Properties of AlScN thin films. In addition, the electrical admittance of AlScN-SAW deposited on polyimide sensor is demonstrated for different Scandium concentrations. The resonant frequencies shift down due to the increases of scandium concentration. The obtained results show that flexible SAW based on c-axis AlScN/PI are promising composite structure for high sensitive sensors
We have fabricated and characterized ZrO2/AlGaN/GaN MIS-HEMTs with "dry-etching free" gate recess structures realized using Selective Area Growth (SAG) of AlGaN barrier on the access regions. The transfer characteristics revealed threshold voltage -0.5 V, suggesting quasi-normally-off operation. In comparison with reference planar HEMTs, the threshold voltage of SAG-HEMTs was shifted by about +5 V towards the positive voltage direction. Moreover, SAG-HEMTs showed almost parallel shift of transfer curves with respect to that of the reference planar devices, suggesting no considerable mobility degradation.
Ensemble Monte Carlo simulation was performed to simulate the current gain cutoff frequency (f T ) of an AlN/GaN HEMT. It was found that the donor density in the source ohmic neutral region should be larger than 5×10 20 cm -3 to precisely calculate the drain current. The calculation results indicated that as high as 1.6 THz of f T was achieved with a gate length of 10 nm.
This paper proposed a GaN-based optocoupler chip with monolithic integration. It differs from commercial photodiode optocouplers consisting of at least two coupled chips. This study monolithically integrated a photodiode and a light emitting diode on a sapphire substrate as a single chip. This approach makes the optical transmission of signal in a thin sapphire substrate with a micro-meter scale transmission path reducing light loss. In the experiment, the measurement results showed that the proposed chip has a great current transfer ratio. It meets commercial specifications and provides a more efficient optocoupler manufacturing solution.
We investigated the effects of high-temperature annealed (HTA) at 880 °C of Al2O3 gate insulator on the performance of AlGaN/GaN MIS-HEMTs. HTA-Al2O3 MIS-capacitors exhibited evidences of spillover of 2DEG from AlGaN/GaN to Al2O3/AlGaN interface. Moreover, HTA-Al2O3 MIS-HEMTs also showed smaller hysteresis in transfer curves and higher maximum drain current compared to those of the reference Al2O3/AlGaN/GaN MIS-HEMTs. These suggest highly improved insulator/semiconductor interfaces by high-temperature annealing of Al2O3 insulator layer.
A new dual-band directional coupler for wireless local area network (WLAN) is proposed to achieve high directivity. Single coupling line couples both 2.4-2.5 GHz and 4.9-5.85 GHz signals. The coupler has been implemented in the SOI CMOS process with an electrostatic static discharge (ESD) protection device. The measurement results showed 0.15 dB insertion loss and 23 dB directivity at 2.4-2.5 GHz, and 0.42 dB and 28 dB at 4.9-5.85 GHz, respectively. Its human body model (HBM) ESD robustness is higher than 4 kV without DC power consumption.
Using a unique characterization method that integrates the power spectral density (PSD) over a given frequency band, we examined the 1/f noise dependence of MOSFET devices and processes. As a result, we were able to identify a slight dependence and a Lorentzian noise that was difficult to determine from the shape of the PSD graph. This new method of quantitatively capturing the differences in stochastic phenomena was shown to be effective in device and process development.
We have studied the effects of oxygen plasma treatment prior to insulator deposition on the electrical performance of AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs). Devices treated with oxygen plasma exhibit more positive threshold voltages, less hysteresis in transfer curves and higher peak transconductance values compared with reference devices without oxygen plasma treatment. Our results suggest that oxygen plasma treatment of the AlGaN surface before insulator deposition can improve the overall electrical performance of GaN-based MIS-HEMTs.
We previously reported a near-infrared (NIR) color fundus camera that can image the fundus without the use of mydriatic agents. Using this technology, pseudo-color images can be reconstructed from images in the three NIR wavelength bands. In this study, we designed and manufactured a five-wavelength bandpass mosaic filter for CMOS image sensors (CIS) by modifying the thickness of the middle layer of a multilayer thin-film structure based on the interference bandpass filter principle. It is possible to acquire information about all bands at all locations on the fundus by using the fixational movement of the human eye. Adapting a fabricated 5-channel CIS, we report the validity of high-spatial-resolution imaging by demosaicing and spectral resolution enhancement by deconvolution processing.
In 2 O 3 thin films were deposited using atomic layer deposition (ALD), which is suitable for deposition on three-dimensional structures. It was applied to thin-film transistors (TFT), where high-mobility was maintained even in thin channels of 10 nm. Furthermore, it was operated as fully depleted mode and normally-off were obtained. It was suggested that the introduction of AlO x passivation layer and annealing process can effectively reduce oxygen vacancies in InO x channel without doping of additive elements.
In this study, the characteristics modeling of a PN-body tied silicon on insulator field-effect transistor, which has super steep subthreshold slope (SS) (less than 10 mV/dec) characteristics, was tried by using a neural network. We found that four or more hidden layers are needed to express the super steep SS.
Integrated circuits on automotive or aerospace applications must have high radiation tolerance. Multiplication such as duplication or triplication is effective for flip-flops (FFs). Clock gating may be used to reduce power consumption. Soft error tolerance depends on multiplexing, and soft error tolerance becomes weak by clock gating. We evaluate soft error tolerance of three types of FFs by α-ray and heavy ion irradiaiton test. According to the results of α-ray irradiation test, the soft-error tolerance of two FFs is 2x or 26x stronger than that of BCDMRFF. Heavy-ions irradiation test shows that the tolerance of the FF, which restore the errors, is 30x or more than that of BCDMRFF.
This paper reports the sensitivity of second order S2 Lamb mode to liquid characteristics, in which an acoustic Lamb mode resonator LWR based on LiNbO3 ZX (LNO) is numerically studied. The sensitivity of the device to liquids loading is enhanced by incorporating distributed micro-channels in the wave path in order to increase the contact surface between the liquid and the acoustic wave. The obtained results contribute in the development of high sensitivity acoustic sensors for liquids characterization.
Nanostructured mixed-conducting oxides are key components for energy conversion and energy storage devices. Improving their functionality is of large importance in order to tackle the growing demand of energy. All nanostructure inherently exhibit a high surface area, which enables tailoring their electrochemical properties by surface engineering. Modifying the surface properties offers the possibility to manipulate electronic and ionic charge transport as well as charge storage in the surface region. In addition, it allows the increase of the thermal and chemical stability of nanostructures by the deposition of a thin protective coating. Due to the large number of possibilities of controlling the electrochemical properties of nanostructures for energy devices, surface engineering plays an important role for the design of efficient energy technologies.
A heterogeneous 3D system integration technology is the key technology to achieve future high-performance and energy efficient systems such as high-performance computer system, AI system, post 5G/6G system and quantum computing system. Current status and future prospect of heterogeneous 3D system integration technology are discussed.
Mist chemical vapor deposition (mist-CVD) is a non-vacuum technique for depositing various metal oxide/sulfite films from relative non-toxic and nonpyrophoric aqueous solution, resulting in relatively simple, low-cost and fast deposition rate under atmospheric pressure. Recent reports have demonstrated the capability of mist-CVD as an able replacement for conventional vacuum deposition methods in some applications. In this work, firstly state-of-the-art literature reports on mist-CVD techniques are reviewed. Finally, we highlight the important progress in mist-CVD deposited-gate insulators for GaN-based metal-insulator-semiconductor (MIS) devices applications.
