• 전자공학회논문지A
• /
• 제29A권2호
• /
• pp.63-67
• /
• 1992

Shallow $p^{+}-n,n^{+}-p$ diodes have been fabricated using rapid thermal diffusion by solid diffusion source and rapid thermal alloying with pure Aluminum. Diode area and junction depth are designed about 2.83$[\times}10^{-3}cm^{2}$ and 250nm, respectively. Electrical characteristics of $p^{+}-n$ diode show that the ideality factor is 1.04 and reverse current density is 29.3nA/$cm^{2}$, respectively. On the other hand, those of $n^{+}-p$ diode show that the ideality factor is 1.05 and reverse current density is 85.2pA/$cm^{2}$. The reverse currents are measured at 5V reverse bias after rapid thermal alloying for all the measurement.

• Current Optics and Photonics
• /
• 제5권2호
• /
• pp.173-179
• /
• 2021

The electroluminescence (EL) intensities of GaN-based light-emitting diodes (LEDs) are estimated based on their photoluminescence (PL) properties. The PL intensity obtained under open-circuit conditions is divided into two parts: the PL intensity under a forward bias lower than the optical turn-on voltage, and the difference between the PL intensities under open-circuit conditions and under forward bias. The luminescence induced by photoexcitation under a constant forward bias lower than the optical turn-on voltage is primarily the PL from the excited area of the LED. In contrast the intensity difference, obtained by subtracting the PL intensity under the forward bias from that under open-circuit conditions, contains the EL induced by the photocarriers generated during photoexcitation. In addition, a reverse photocurrent is generated during photoexcitation under constant forward bias across the LED, and can be correlated with the PL-intensity difference. The relationship between the photocurrent and PL-intensity difference matches well the relationship between the injection current and EL intensity of LEDs. The ratio between the photocurrent generated under a bias and the short-circuit current is related to the ratio between the PL-intensity difference and the PL intensity under open-circuit conditions. A relational expression consisting of the ratios, short-circuit current, and PL under open-circuit conditions is proposed to estimate the EL intensity.

• 한국전기전자재료학회논문지
• /
• 제19권9호
• /
• pp.818-824
• /
• 2006

The effects of high-temperature process required to fabricate the SiC devices on the surface morphology and the electrical characteristics were investigated for 4H-SiC Schottky diodes. The 4H-SiC diodes without a graphite cap layer as a protection layer showed catastrophic increase in an excess current at a forward bias and a leakage current at a reverse bias after high-temperature annealing process. Moreover it seemed to deviate from the conventional Schottky characteristics and to operate as an ohmic contact at the low bias regime. However, the 4H-SiC diodes with the graphite cap still exhibited their good electrical characteristics in spite of a slight increase in the leakage current. Therefore, we found that the graphite cap layer serves well as the protection layer of silicon carbide surface during high-temperature annealing. Based on a closer analysis on electric characteristics, a conductive surface transfiguration layer was suspected to form on the surface of diodes without the graphite cap layer during high-temperature annealing. After removing the surface transfiguration layer using ICP-RIE, Schottky diode without the graphite cap layer and having poor electrical characteristics showed a dramatic improvement in its characteristics including the ideality factor[${\eta}$] of 1.23, the schottky barrier height[${\Phi}$] of 1.39 eV, and the leakage current of $7.75\{times}10^{-8}\;A/cm^{2}$ at the reverse bias of -10 V.

• 한국전기전자재료학회논문지
• /
• 제20권10호
• /
• pp.912-917
• /
• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

• 한국재료학회지
• /
• 제30권7호
• /
• pp.333-337
• /
• 2020

Orthorhombic DyMnO₃ films are fabricated epitaxially on Nb-1.0 wt%-doped SrTiO₃ single crystal substrates using pulsed laser deposition technique. The structure of the deposited DyMnO₃ films is studied by X-ray diffraction, and the epitaxial relationship between the film and the substrate is determined. The electrical transport properties reveal the diodelike rectifying behaviors in the all-perovskite oxide junctions over a wide temperature range (100 ~ 340 K). The forward current is exponentially related to the forward bias voltage, and the extracted ideality factors show distinct transport mechanisms in high and low positive regions. The leakage current increases with increasing reverse bias voltage, and the breakdown voltage decreases with decrease temperature, a consequence of tunneling effects because the leakage current at low temperature is larger than that at high temperature. The determined built-in potentials are 0.37 V in the low bias region, and 0.11 V in the high bias region, respectively. The results show the importance of temperature and applied bias in determining the electrical transport characteristics of all-perovskite oxide heterostructures.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제17권2호
• /
• pp.239-244
• /
• 2017

We experimentally investigate the physical mechanism for asymmetrical degradation in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) under simultaneous gate and drain bias stresses. The transfer curves exhibit an asymmetrical negative shift after the application of gate-to-source ($V_{GS}$) and drain-to-source ($V_{DS}$) bias stresses of ($V_{GS}=24V$, $V_{DS}=15.9V$) and ($V_{GS}=22V$, $V_{DS}=20V$), but the asymmetrical degradation is more significant after the bias stress ($V_{GS}$, $V_{DS}$) of (22 V, 20 V) nevertheless the vertical electric field at the source is higher under the bias stress ($V_{GS}$, $V_{DS}$) of (24 V, 15.9 V) than (22 V, 20 V). By using the modified external load resistance method, we extract the source contact resistance ($R_S$) and the voltage drop at $R_S$ ($V_{S,\;drop}$) in the fabricated a-IGZO TFT under both bias stresses. A significantly higher RS and $V_{S,\;drop}$ are extracted under the bias stress ($V_{GS}$, $V_{DS}$) of (22 V, 20V) than (24 V, 15.9 V), which implies that the high horizontal electric field across the source contact due to the large voltage drop at the reverse biased Schottky junction is the dominant physical mechanism causing the asymmetrical degradation of a-IGZO TFTs under simultaneous gate and drain bias stresses.

• 한국유체기계학회 논문집
• /
• 제18권6호
• /
• pp.27-30
• /
• 2015

In this study, we attempted to harvest energy using water droplet based on Reverse Electro Wetting On Dielectric (REWOD) phenomenon between water droplet and dielectric surface without external bias. REWOD device can be fabricated via simple coating process, which is highly economic and easy. We believe that our system is well-suited for IoT(Internet of Things) embedded electronics that require low but consistent electricity. Moreover, our device can be integrated with window to generate electricity upon raindrops.

• 한국정보통신학회논문지
• /
• 제5권1호
• /
• pp.157-165
• /
• 2001

집적 쇼트키 논리 게이트에서 전압 스윙을 크게 하기 위해서 백금 실리사이드 쇼트키 접합의 전기직 특성을 분석하였고, 이 접합에서 프로그램으로 특성을 시뮬레이션 하였다. 분석특성 특성을 위한 시뮬레이션 프로그램은 제조 공정용 SUPREM V와 모델링용 Matlab, 소자 구조용의 Medichi 툴이다. 시뮬레이션 특성을 위한 입력 파라미터는 소자 제작 공정의 공정 단계와 동일한 조건으로 하였다. 분석적인 전기적인 특성들은 순방향 바이어스에서 턴-온 전압, 포화 전류, 이상인자이고, 역방향 바이어스에서 항복 전압을 실제 특성과 시뮬레이션 특성 사이의 결과를 보였다. 결과로써 순방향 턴-온 전압, 역방향 항복전압, 장벽 높이는 기판의 증가된 농도의 변화에 따라 감소되었지만, 포화전류와 이상인자는 증가되었다.

• 한국멀티미디어학회논문지
• /
• 제3권5호
• /
• pp.535-541
• /
• 2000

본 논문은, ISL의 전압 스윙을 개선시키기 위한 쇼트키 접합의 특성 분석과 이 접합을 프로그램으로 특성을 시뮬레이션하였다. 특 분석용 시뮬레이션 프로그램은 SUPREM V, SPICE, Medichi, Matlab이다. 쇼트키 접합은 백금 실리사이드와 실리콘의 정류성 접촉이며, 실리콘의 n형 기판 농도 방법은 이온 주입법이며, 온도 변화에 따라서 쇼트키 접합의 특성을 측정과 분석하였고, 프로그램으로 특성을 동일 조건에서 시뮬레이션 하였다. 분석 파라미터는 순방향에서 턴온 전압, 포화 전류, 이상인자이고, 역방향에서 항복전압의 실제 특성과 시뮬레이션 특성 결과를 제시하였다. 결과로써, 순방향 턴온 전압, 역방향 항복전압, 장벽높이는 기판 농도의 증가에 따라 감소하였지만, 포화전류와 이상인자는 증가되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.232-233
• /
• 2008

The 4H-SiC schottky diodes treated by the various dry etch methods were fabricated and electrically characterized. The post etch process including an Inductively Coupled Plasma(ICP) etch and a Neutron Beam Etch(NBE) was performed after a high-temperature activation annealing without graphite cap in order to eliminate the damaged surface generated during the activation annealing. The reverse leakage current of diode treated by ICP was 1/35 times lower than that of the diode without any post etch at the anode bias of -100V, while the reverse leakage current of diode treated by NBE was 1/44 times lower at the same bias.