http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Normally-off AlGaN/GaN-based MOS-HEMT with self-terminating TMAH wet recess etching
Son, Dong-Hyeok,Jo, Young-Woo,Won, Chul-Ho,Lee, Jun-Hyeok,Seo, Jae Hwa,Lee, Sang-Heung,Lim, Jong-Won,Kim, Ji Heon,Kang, In Man,Cristoloveanu, Sorin,Lee, Jung-Hee Elsevier 2018 Solid-state electronics Vol.141 No.-
<P><B>Abstract</B></P> <P>Normally-off AlGaN/GaN-based MOS-HEMT has been fabricated by utilizing damage-free self-terminating tetramethyl ammonium hydroxide (TMAH) recess etching. The device exhibited a threshold voltage of +2.0 V with good uniformity, extremely small hysteresis of ∼20 mV, and maximum drain current of 210 mA/mm. The device also exhibited excellent off-state performances, such as breakdown voltage of ∼800 V with off-state leakage current as low as ∼10<SUP>−12</SUP> A and high on/off current ratio (I<SUB>on</SUB>/I<SUB>off</SUB>) of 10<SUP>10</SUP>. These excellent device performances are believed to be due to the high quality recessed surface, provided by the simple self-terminating TMAH etching.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Normally-off was achieved by self-terminating TMAH wet etching. </LI> <LI> Hysteresis of threshold voltage was smaller than 50 mV. </LI> <LI> Self-terminating recess showed good distribution of threshold voltage for 30 devices. </LI> </UL> </P>
AlGaN/GaN heterostructure pH sensor with multi-sensing segments
Dong, Yan,Son, Dong-hyeok,Dai, Quan,Lee, Jun-Hyeok,Won, Chul-Ho,Kim, Jeong-Gil,Kang, Seung-Hyeon,Lee, Jung-Hee,Chen, Dunjun,Lu, Hai,Zhang, Rong,Zheng, Youdou Elsevier 2018 Sensors and actuators. B, Chemical Vol.260 No.-
<P><B>Abstract</B></P> <P>pH sensor is very important in various fields, and has triggered many types of devices based on different materials and mechanisms. How to improve the performances of the sensors is one of major challenges now. In the present paper, we developed an idea to improve the sensitivity of pH sensors based on AlGaN/GaN high-electron-mobility transistors (HEMTs) by introducing multi-sensing segments, and experimentally fabricated prototype devicesand then investigated their responses to aqueous solutions under different pH values. The optimized sensor exhibits a very high linear sensitivity of 1.35 mA/pH at drain-source voltage of 1.5 V, which is much higher than those of conventional pH sensors with single open gate sensing area. This indicates that the multi-sensing segments is very effective in increasing the sensitivity of the pH sensor, rather than simply increasing the sensing area. The sensors degrade after measurement in solution for a long working time, but they can recover to their initial states in a certain duration after washing, typically ∼24 h. Our finding paves new strategy for the future design of high sensitive and stable pH sensors based on HEMTs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel multi-sensing segments pH sensor is designed and fabricated by using AlGaN/GaN high electron mobility transistor. </LI> <LI> Realizing very high sensitivity on the multi-sensing sensor, which is much higher than that of conventional geometric pH sensor. </LI> <LI> Achieved excellent performance stability with good recovery feature on the multi-sensing sensor. </LI> </UL> </P>
Low voltage operation of GaN vertical nanowire MOSFET
Son, Dong-Hyeok,Jo, Young-Woo,Seo, Jae Hwa,Won, Chul-Ho,Im, Ki-Sik,Lee, Yong Soo,Jang, Hwan Soo,Kim, Dae-Hyun,Kang, In Man,Lee, Jung-Hee Elsevier 2018 Solid-state electronics Vol.145 No.-
<P><B>Abstract</B></P> <P>GaN gate-all-around (<I>GAA</I>) vertical nanowire MOSFET (<I>VNWMOSFET</I>) with channel length of 300 nm and diameter of 120 nm, the narrowest GaN-based vertical nanowire transistor ever achieved from the top-down approach, was fabricated by utilizing anisotropic side-wall wet etching in TMAH solution and photoresist etch-back process. The <I>VNWMOSFET</I> exhibited output characteristics with very low saturation drain voltage of less than 0.5 V, which is hardly observed from the wide bandgap-based devices. Simulation results indicated that the narrow diameter of the <I>VNWMOSFET</I> with relatively short channel length is responsible for the low voltage operation. The <I>VNWMOSFET</I> also demonstrated normally-off mode with threshold voltage (<I>V<SUB>TH</SUB> </I>) of 0.7 V, extremely low leakage current of ∼10<SUP>−14</SUP> A, low drain-induced barrier lowering (<I>DIBL</I>) of 125 mV/V, and subthreshold swing (<I>SS</I>) of 66–122 mV/decade. The GaN <I>GAA VNWMOSFET</I> with narrow channel diameter investigated in this work would be promising for new low voltage logic application.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GaN vertical nanowire MOSFET is fabricated by top-down approach. </LI> <LI> Saturation voltage below 0.5 V is due to the small diameter and carrier concentration of channel. </LI> <LI> Both normally-off and good off-state performances are achieved from gate-all-around structure of channel. </LI> <LI> GaN vertical nanowire MOSFET is also promising for low voltage logic applications. </LI> </UL> </P>
손동혁(Dong-Hyeok Son),최다운(Da-Woon Choi),김명수(Myung-Su Kim),강인준(In-Jun Kang),김병국(Byung-Kuk Kim),조윤현(Yun-Hyun Cho) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
본 연구는 영구자석 AC 동기전동기의 초기 기동제어에 대하여 연구하였다. 회전자 위치 검출용 센서는 홀센서를 사용하였고 전동기 운전을 벡터제어를 사용하기 위해 전동기가 정지된 상태에서 홀센서 신호에 따른 회전자 위치를 계산하였다. 견인전동기가 주행저항 보다 큰 견인력을 내기 위해 전동기를 BLDC로 기동한 후 안정적 운전을 위해서 벡터제어로 전환하였다.
Jong Hyeok Kwak(곽종혁),Jae Beom Jeong(정재범),Bong Kyeong Son(손봉경),Soon Ki Sung(성순기),Seong Jin Kim(김성진),Dong Won Kang(강동원),Chan Hyeok Park(박찬혁),Hyeon Wha Im(임현화),Yu Hui Lee(이유희),Bong Sang Lee(이상봉),Dong hye 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.2
The fractional anisotropy value of the basal ganglia fibers in the brain gray matter region was analyzed by Tract-Based Spatial Statics(TBSS) method after acquiring the diffusion tensor image to identify the presence or absence of brain white matter damage to smoking in male. As a result of measurement analysis, the fractional anisotropy measurement value was lower in smokers than non–smokers in all areas, and the FA value was statistically significant. smoking significantly affects all the anatomic micro structural changes in the brain gray matter and damages the nerve fiber tract. As a result, it can affects functional abnormalities related to the minute changes of the brain due to smoking. 흡연 유무의 남성을 대상으로 뇌 회백질의 손상 유무를 파악 할 수 있는 확산텐서영상을 검사하여 영상을 획득 한 후 Tract-Based Spatial Statics(TBSS)방법으로 뇌 회백질 부위의 기저핵 신경섬유로의 비등방도 FA(fractional anisotropy)값을 측정 분석한 결과 모든 영역에서 흡연자가 비흡연자보다 비등방성 측정값이 낮게 관찰되었으며 FA값은 통계적으로 유의하였다. 본 연구의 측정한 FA결과 값으로 추측하자면 즉, 흡연이 뇌 회백질 기저핵의 모든 해부학적 미세 구조성 변화에 크게 영향을 미치며 신경섬유로를 손상시키고 이와 관련된 기능적 이상에 영향을 준다고 할 수 있다.
손동혁(Dong-Hyeok Son),최다운(Da-Woon Choi),김명수(Myung-Su Kim),김병국(Byung-Kuk Kim),조윤현(Yun-Hyun Cho) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
본 연구는 홀센서를 이용한 PMSM의 벡터제어에 대하여 연구하였다. 회전자 위치 검출용 센서는 홀센서를 사용하였고 전동기 운전을 벡터제어를 사용하기 위해 전동기가 정지된 상태에서 홀센서 신호에 따른 회전자 위치를 계산하였다. 견인전동기가 주행저항 보다 큰 견인력을 내기 위해 전동기를 BLDC로 기동한 후 안정적 운전을 위해서 벡터제어로 전환하였다.
인버터 구동 유도전동기의 고정자 권선 단락 시 자속센서를 이용한 고장진단
손동혁(Dong-Hyeok Son),김도선(Do-Sun Kim),황돈하(Don-Ha Hwang),조윤현(Yun-Hyun Cho) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
본 논문에서는 유도전동기에서 발생되는 고장들 중에서 고정자 권선 단락 고장 특성 해석과 고장 판별에 대한 방법을 제시한다. 고정자 권선 단락을 판별하기 위해서 단락상태의 고정자를 모델링 하여 3상 전류 불평형과 공극자속밀도에 대한 유한요소해석을 수행하였다. 유한요소해석으로 얻어진 결과의 타당성을 입증하기 위해 실험을 통하여 전류와 공극자속에 대한 유기기전력 측정값을 비교하였다. 공극자속의 유기기전력을 측정하기 위해 고정자 슬롯에 자속센서를 취부하였다. 고정자 권선 단락 시 3상 전류는 불평형을 이루고 공극자속밀도가 감소되어 유도전동기의 고정자 고장을 판별하는 기초자료가 된다.
홀센서를 이용한 모노레일 PMSM 견인전동기의 벡터제어
손동혁(Dong-Hyeok Son),김명수(Myoung-Su Kim),최다운(Da-Woon Choi),조윤현(Yun-Hyun Cho) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.7
This paper supposes the vector control algorithm to estimate the rotor position of permanent magnet synchronous traction motor using the hall-effect sensor. The hall-effect provides 60 electrical degrees resolution in rotor position sensing and it is very low resolution. The algorithm makes resolution high as optical encoders or electromagnetic resolver. If necessary, the reference rotor position angle is controlled by adjusting the variable. When a rotor position sensor such as either a optical encoder or a electromagnetic resolver is misalignment, it is useful to align with those. The method on adjusting the reference rotor position angle can compensate for misalignment error degrees by 60 electrical degrees.