• Journal of IKEEE
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• v.22 no.3
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• pp.706-711
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• 2018

In this work, we have investigated the characteristics of 4H-SiC metal-oxide-semiconductor (MOS) devices with silicon oxynitride (SiON) insulator using plasma enhanced chemical vapor deposition (PECVD). After post metallization annealing, the trap densities of the fabricated devices decreased significantly. In particular, the device annealed at $500^{\circ}C$ in forming gas ambient exhibited excellent MOS characteristics along with negligible hysteresis, which proved the potential of PECVD SiON as an alternative gate insulator for use in 4H-SiC MOS device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.806-813
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• 2009

This paper presents a modem chip design for high-speed wireless communications. Among the high-speed communication technologies, we design the UWB (Ultra-Wideband) modem SoC (System-on-Chip) Chip based on a MB-OFDM scheme which uses wide frequency band and gives low frequency interference to other communication services. The baseband system of the modem SoC chip is designed according to the standard document published by WiMedia. The SoC chip consists of FFT/IFFT (Fast Fourier Transform/Inverse Fast Fourier Transform), transmitter, receiver, symbol synchronizer, frequency offset estimator, Viterbi decoder, and other receiving parts. The chip is designed using 90nm CMOS (Complementary Metal-Oxide-Semiconductor) procedure. The chip size is about 5mm x 5mm and was fab-out in July 20th, 2009.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.462-469
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• 2008

In this paper, we design the FPGA (Field-Programmable Gate Array) of the KOINONIA WPAN (Wireless Personal Area Network), and implement the SoC (System on Chip). We use the redundant bits to make a constant-amplitude in a modulator part. Additionally, the SNR (Signal to Noise Ratio) performance of the demodulator is improved by using the redundant bits in decoding steps. The four-million FPGA of the KOINONIA WPAN can be operated at 44MHz frequency. The PER (Packet Error Rate) of the designed FPGA with RF (Radio Frequency) module is below 1% at the -86dB MIPLS (Minimum Input Power Level Sensitivity), and the SNR is about 13dB. The SoC is implemented by using Hynix 0.25um CMOS (Complementary Metal Oxide Semiconductor) process. The size of the SoC is $6.52mm{\times}6.92mm$.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.949-958
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• 2018

A voice recognition control system is a system for controlling a peripheral device by recognizing a voice. Recently, a voice recognition control system have been applied not only to smart devices but also to various environments ranging from IoT(: Internet of Things), robots, and vehicles. In such a voice recognition control system, the recognition rate is lowered due to the ambient noise in addition to the voice of the user. In this paper, we propose a dual channel acoustic beamforming hardware architecture for MEMS(: Microelectromechanical Systems) microphones to eliminate ambient noise in addition to user's voice. And the proposed hardware architecture is designed as ASIC(: Application-Specific Integrated Circuit) using TowerJazz $0.18{\mu}m$ CMOS(: Complementary Metal-Oxide Semiconductor) technology. The designed dual channel acoustic beamforming ASIC has a die size of $48mm^2$, and the directivity index of the user's voice were measured to be 4.233㏈.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.303-307
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• 2006

In this paper, we have designed the p-type metal-oxide semiconductor field-effect transistor(pMOSFET) for SiGe devices with gate lengths of $0.9{\mu}m$ and $0.1{\mu}m$using the TCAD simulators. The electrical characteristics of devices have been investigated over the temperatures of 300 and 77K. We have used the two carrier transfer models(hydrodynamic model and drift-diffusion model). We how that the drain current is higher in the hydrodynamic model than the drift-diffusion model. When the gate length is $0.9{\mu}m$, the threshold voltage shows -0.97V and -1.15V for 300K and 77K, respectively. The threshold voltage is, however, nearly same at $0.1{\mu}m$ for 300K and 77K.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.328-335
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• 2010

We have designed and fabricated an active pixel sensor(APS) using an optimized n-well/gate-tied p-channel metal oxide semiconductor field effect transistor(PMOSFET)-type photodetector with a built-in transfer gate. This photodetector has a floating gate connected to n-well and a built-in transfer gate. The photodetector has been optimized by changing the length of the transfer gate. The APS has been fabricated using a 0.35 ${\mu}m$ standard complementary metal oxide semiconductor(CMOS) process. It was confirmed that the proposed APS has a wider dynamic range than the APS using the previously proposed photodetector and a higher sensitivity than the conventional APS using a p-n junction photodiode.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.157-159
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• 2010

Most digital cameras apply a Charge Coupled Device(CCD) Sensor or a Complementary Metal Oxide Semiconductor(COMS) Sensor. And the images captured these sensors include unwanted noises. In this paper, we proposed a method of the Noise Reduction(NR) about noise reduction or recovery in the image. The proposed NR method is related to Bandwidth of the Low Pass Filter(LPF). For improvement of NR, we were changing the filter coefficient of the LPF. The results of simulations with various filter coefficients, [1 2 1] in the LPF and [-1 2 -1] in the High Pass Filter(HPF) have ideal frequency bandwidth and high performance. We proposed a filter coefficient [1 2 1] and [-1 2 -1] in the LPF and the HPF respectively.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.621-626
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• 2017

In this paper, an optical dosimetric system for radiation dose measurement is developed and characterized for 100 MeV proton beams in KOMAC(Korea Multi-Purpose Accelerator Complex). The system consists of 10 wt% Ultima GoldTM liquid organic scintillator in the ethanol, a camera lens(50 mm / f1.8), and a high sensitivity CMOS(complementary metal-oxide-semiconductor) camera (ASI120MM, ZWO Co.). The FOV(field of view) of the system is designed to be 150 mm at a distance of 2 m. This system showed sufficient linearity in the range of 1~40 Gy for the 100 MeV proton beams in KOMAC. We also successfully got the percentage depth dose and the isodose curves of the 100 MeV proton beams from the captured images. Because the solvent is not a human tissue equivalent material, we can not directly measure the absorbed dose of the human body. Through this study, we have established the optical dosimetric procedure and propose a new volume dose assessment method.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.87-96
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• 2019

Flexible organic light-emitting diode (OLED) displays with organic thin-film transistors (OTFTs) backplanes have been studied. A gate driver is required to drive the OLED display. The gate driver is integrated into the panel to reduce the manufacturing cost of the display panel and to simplify the module structure using fabrication methods based on low-temperature, low-cost, and large-area printing processes. In this paper, pseudo complementary metal oxide semiconductor (CMOS) logic gates are implemented using OTFTs for the gate driver integrated in the flexible OLED display. The pseudo CMOS inverter and NAND gates are designed and fabricated on a flexible plastic substrate using inkjet-printed OTFTs and the same process as the display. Moreover, the operation of the logic gates is confirmed by measurement. The measurement results show that the pseudo CMOS inverter can operate at input signal frequencies up to 1 kHz, indicating the possibility of the gate driver being integrated in the flexible OLED display.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.311-317
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• 2019

We first numerically analyzed the characteristics of a silicon-based grating structure for beam steering. The analysis includes the basic principle of the grating structure according to the wavelength, peak radiation angle, radiation efficiency, and full-width at the half maximum(FWHM) of the radiation angle. Based on the analysis, we propose a silicon-based grating structure integrated with distributed Bragg reflector(DBR) to obtain a high radiation efficiency and narrow beam width simultaneously. We performed the numerical optimization of the radiation efficiency and FWHM of the radiation angle according to the DBR position. By the design optimization using the proposed grating structure compatible with the complementary metal-oxide semiconductor(CMOS) process, we achieved a maximum radiation efficiency of 87.1% and minimum FWHM of radiation angle of $4.68^{\circ}$.