다공질 실리콘 산화막의 계면 및 절연파괴 ( Interface and Dielectric Breakdown Characteristics of Oxidized Porous Silicon Films )

최복길,강희복,성영권 대한전자공학회 1990 대한전자공학회 학술대회 Vol.1990 No.1

RF 스퍼터된 바나듐 산화막의 습도 감지 특성

최복길,최창규,김성진 대한전기학회 2006 전기학회논문지C Vol.55 No.10C

- Vanadium oxide thin films (VOx) have been deposited by RF magnetron sputtering from V2O5 target under different oxygen partial pressure ratios(0%, 10%) and substrate temperatures(27℃, 400℃). Crystallographic structure and morphology of the films are studied by XRD and SEM. Humidity-sensing properties of resistive sensors having interdigitated electrode structure are characterized through electrical conduction measurements. The films deposited at room temperature are amorphous whereas the ones deposited above 400℃ are polycrystalline. The sensors show good response to humidity over 20%RH to 80%RH. Vanadium oxide thin films deposited with 0%O2 partial pressure at 400℃ exhibit greater sensitivity to humidity change than others.

스퍼터링으로 퇴적시킨 바나듐 산화막의 구조적, 광학적 특성에 미치는 산소 어닐링의 효과

최복길,최창규,김성진 한국전기전자재료학회 2000 전기전자재료학회논문지 Vol.13 No.12

Thin films of vanadium oxide(VOx) have been deposited by r.f. magnetron sputtering from V$_2$O$\_$5/ target in gas mixture of argon and oxygen. Crystal structure, surface morphology, chemical composition, molecular structure and optical properites of films in-situ annealed in O$_2$ambient with various heat-treatment conditions are characterized through XRD, SEM, AES, RBS, RTIR and optical absorption measurements. The films annealed below 200$\^{C}$ are amorphous, and those annealed above 300$\^{C}$ are polycrystalline. The growth of grains and the transition of vanadium oxide into the higher oxide have been observed with increasing the annealing temperature and time. The increase of O/V ratio with increasing the annealing temperature and time is attributed to the diffusion of oxygen and the partial filling of oxygen vacancies. It is observed that the oxygen atoms located on the V-O plane of V$_2$O$\_$5/ layer participate more readily in the oxidation process. Also indirect and direct optical band gaps were increased with increasing the annealing temperature and time.

α-Fe₂O₃ thermistor의 전기적 특징에 미치는 계면효과

최복길 공주대학교 기초과학연구소 1992 論文集 Vol.30 No.1

The dependence of capacitance on measuring temperature, I-V, C-V, and DLTS properties have been measured on polycrystalline samples of α-Fe2O3 containing small amounts of added titanium. The effects of grain boundary states on the electrical conduction mechanism in the ceramic semiconductor oxides have been investigated. The NTC mechanism of thermistor can be explained by the model of double Schottky barrier at the grain boundary with hopping conduction. It is found from DLTS measurement that interface states exist in the grain boundary and have an effect on electrical conduction. From these experiments we can suppose that trapping and detrapping of carier at the grain boundary states to temperature variation may be a major cause of NTC mechanism of α-Fe2O3 thermistor containing N-type impurities.

다공질 실리콘 산화막의 형성기구 및 계면특성

최복길 公州大學校工科大學生産技術硏究所 1993 論文集 Vol.1 No.-

HF용액내에서 양극 반응에 의해 형성된 다공질 실리콘층(PSL)의 특성을 조사하고 다공질 실리콘 산화막(OPS)의 형성 기구와 계면 특성을 규명하였다. SIMS분석을 통한 PSL의 밀도는 표면보다 PSL-Si 계면이 높으며 산화 반응이 PSL의 표면 및 내부의 세공 표면에서 균일하게 이루어진다. OPS막은 열산화 Sio₂에 비해 큰 프랫밴드 전압과 고정 전하 밀도를 나타내며 dlts법으로 측정한 OPS막의 포획 단면적과 계면 상태 밀도는 각각 10?㎠와 10?-10?eV?의 범위이다. The properties of porous silicon layer(PSL) formed by anodic reaction in hydroffluoric acid solution have been studied. Ferther, the formation mechanism and interface characteristics of oxidized porous silicon(OPS) film are reported. It is shown from SIMS analysis that the porous silicon nera the surface has a lower density than that near the PSL-substrate interface and that oxidation is performed uniformly through PSL. OPS film shows higher flat-band voltage and fixed charge density than thermally grown SiO₂ film. The capture cross-section and the interface states density of OPS film determined by DLTS method are of the order of 10?㎠ and 10??-10??cm?eV?? respectively.

진공 어닐링한 바나듐 산화악의 구조적, 전기적 특성

최복길,최창규,권광호,김성진,Choi Bok-Gil,Choi Chang-Kyu,Kwon Kwang-Ho,Kim Sung-Jin 대한전기학회 2005 전기학회논문지C Vol.54 No.1

Thin films of vanadium oxide(VO/sub x/) were deposited by r.f. magnetron sputtering from V₂O/sub 5/ target with oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% and in situ annealed in vacuum at 400℃ for 1h and 4h. Crystal structure, chemical composition, molecular structure, optical and electrical properties of films were characterized through XRD, XPS, RBS, FTIR, optical absorption and electrical conductivity measurements. The films as-deposited are amorphous, but 0%O₂ films annealed for time longer than 4h and 8% O₂ films annealed for time longer than 1h are polycrystalline. As the oxygen partial pressure is increased the films become more stoichiometric V₂O/sub 5/. When annealed at 400℃, the as-deposited films are reduced to a lower oxide. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Electrical conductivity and thermal activation energy are increased with increasing the annealing time and with decreasing the oxygen partial pressure.

스퍼터링으로 증착된 바나듐 산화막의 구조적, 광학적, 전기적 특성에 미치는 산소 분압의 효과

최복길,최창규,권광호,김성진,이규대 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.12

Thin films of vanadium oxide(VO$\_$x/) have been deposited by r.f. magnetron sputtering from V$_2$O$\_$5/ target in gas mixture of argon and oxygen. The oxygen/(oxygen+argon) partial pressure ratio is changed from 0% to 8%. Crystal structure, chemical composition, bonding, optical and electrical properties of films sputter-deposited under different oxygen gas pressures are characterized through XPS, AES, RBS, FTIR, optical absorption and electrical conductivity measurements. V$_2$O$\_$5/ and lower oxides co-exist in sputter-deposited films and as the oxygen partial pressure is increased the films become more stoichiometric V$_2$O$\_$5/. The increase of O/V ratio with increasing oxygen gas pressure is attributed to the partial filling of oxygen vacancies through diffusion. It is observed that the oxygen atoms located on the V-O plane of V$_2$O$\_$5/ layer participate more readily in the oxidation process. With increasing oxygen gas pressure indirect and direct optical band gaps are increased, but thermal activation energies are decreased.

진공 어닐링한 바나듐 산화막의 구조적, 전기적 특성

최복길,최창규,권광호,김성진 대한전기학회 2005 전기학회논문지C Vol.54 No.1(C)

Thin films of vanadium oxide(VOx) were deposited by r.f. magnetron sputtering from V2O5 target with oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% and in situ annealed in vacuum at 400℃ for 1h and 4h. Crystal structure, chemical composition, molecular structure, optical and electrical properties of films were characterized through XRD, XPS, RBS, FTIR, optical absorption and electrical conductivity measurements. The films as-deposited are amorphous, but 0%O2 films annealed for time longer than 4h and 8%O2 films annealed for time longer than 1h are polycrystalline. As the oxygen partial pressure is increased the films become more stoichiometric V2O5. When annealed at 400℃, the as-deposited films are reduced to a lower oxide. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Electrical conductivity and thermal activation energy are increased with increasing the annealing time and with decreasing the oxygen partial pressure.

전자식 ballast의 시험용 의사부하에 관한 연구

이규대,이윤섭,최복길 公州大學校工科大學生産技術硏究所 1994 論文集 Vol.2 No.-

형광들을 점등시키는 안정기의 역할은 형광등과 같이 부저항특성을 갖는 방전등에 과전류가 유입되어, 파괴되지 않도록 일정전압 및 전류를 유지시켜주는 것이다. 최근 사용되고 있는 전자식안정기는 25-30KHz의 주파수를 사용, 캐패시터에 의한 안정화전류를 유도하고 있다. 그러나 전자식안정기는 고주파를 사용하는 관계로 제품의 품질보증을 위한 제반 규정이 까다로워 생산자는 개개의 안정기를 실제 형광등을 사용하여 특성검사를 하고 있다. 본 논문에서는 전자식안정기 특성검사의 효율성을 제고하기 위해 실제 형광등과 동일한 특성을 갖는 의사부하의 설계에 관하여 연구하였다. 초기의 과도 조건을 고려하지 않는 정전압 특성을 갖는 의사부하를 설계하여 실험한 결과 제한된 조건하에서 사용될 수 있음을 확인하였다. The electronic ballast has a role of taking a stable current of fluorescent lamp, which has a characteristics of negative resistance. Recently, it has been designed and operated on using the regulated constant current with capacitor and high frequency of 25 to 30KHz. But a fabricated electronic ballast in an assembly line was difficult to test, because it used a high frequency and needed strict provisions. And then manufacturer is now testing each ballast with a real fluorescent lamp. In this paper, we studied that real lamp can be replaced by a dummy load with the same characteristics.

스퍼터된 바나듐 산화막의 구조적, 광학적 특성에 미치는 기판 온도의 효과

이규대,최복길 公州大學校工科大學生産技術硏究所 1998 論文集 Vol.6 No.-

Thin films of vanadium pentoxide(V₂O5) have been deposited by r.f. magnetron sputtering from V₂O5 target in gas mixture of argon and oxygen. Crystal structure, surface morphology, surface composition and optical properties of films prepared under different substrates are characterized through XRD, SEM, AES, XPS and optical absorption measurements. The films prepared below 100℃ are amorphous, and those prepared above 200℃ are polycrystalline. Thermally Induced oxidation of films into higher oxide has been observed with increasing substrate temperature. Vanadium oxide films show two optical absorption bands indicating the presence of direct and indirect transitions.