• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.430-430
• /
• 2008

Using multi plasma enhanced chemical vapor deposition system (Multi-PECVD), p-a-Si:H deposition layer as a $p^+$ region which was annealed by laser (Q-switched fiber laser, $\lambda$ = 1064 nm) on an n-type single crystalline Si (100) plane circle wafer was prepared as new doping method for single crystalline interdigitated back contact (IBC) solar cells. As lots of earlier studies implemented, most cases dealt with the excimer (excited dimer) laserannealing or crystallization of boron with the ultraviolet wavelength range and $10^{-9}$ sec pulse duration. In this study, the Q-switched fiber laser which has higher power, longer wavelength of infrared range ($\lambda$ = 1064 nm) and longer pulse duration of $10^{-8}$ sec than excimer laser was introduced for uniformly deposited p-a-Si:H layer to be annealed and to make sheet resistance expectable as an important process for IBC solar cell $p^+$ layer on a polished n-type Si circle wafer. A $525{\mu}m$ thick n-type Si semiconductor circle wafer of (100) plane which was dipped in a buffered hydrofluoric acid solution for 30 seconds was mounted on the Multi-PECVD system for p-a-Si:H deposition layer with the ratio of $SiH_4:H_2:B_2H_6$ = 30:120:30, at $200^{\circ}C$, 50 W power, 0.2 Torr pressure for 20 minutes. 15 mm $\times$ 15 mm size laser cut samples were annealed by fiber laser with different sets of power levels and frequencies. By comparing the results of lifetime measurement and sheet resistance relation, the laser condition set of 50 mm/s of mark speed, 160 kHz of period, 21 % of power level with continuous wave mode of scanner lens showed the features of small difference of lifetime and lowering sheet resistance than before the fiber laser treatment with not much surface damages. Diode level device was made to confirm these experimental results by measuring C-V, I-V characteristics. Uniform and expectable boron doped layer can play an important role to predict the efficiency during the fabricating process of IBC solar cells.

• 전기전자학회논문지
• /
• 제23권3호
• /
• pp.832-838
• /
• 2019

본 논문에서는 차세대 전력 반도체 소자인 4H-SiC MOSFET에 대해 연구하였다. 특히 3300V급에서 기존의 DMOSFET 구조보다 개선된 전기적 특성을 갖는 Semi-SuperJunction MOSFET 구조를 제안하였으며, TCAD 시뮬레이션을 통해 기존의 MOSFET과 전기적 특성을 비교 분석하였다. Semi-SJ MOSFET 구조는 부분적으로 SJ를 도입한 구조로, 2차원의 공핍 효과를 통해 전계 분포가 개선되며, 항복 전압이 증가한다. 항복 전압의 개선을 통해 얻은 이득으로, 높은 농도의 도핑이 가능하기 때문에 온 저항을 개선시킬 수 있다. 제안한 Semi-SJ MOSFET 구조는 DMOSFET보다 항복 전압이 8% 감소하지만, 온 저항이 80% 감소한다. 또한 DMOSFET 구조를 개선한 Current Spreading Layer(CSL)구조에 비해서도 온 저항이 44% 감소한다.

• Transactions on Electrical and Electronic Materials
• /
• 제14권1호
• /
• pp.32-35
• /
• 2013

In this paper, a manufacturing process was developed for fabricating high-quality AlGaN/GaN high electron mobility transistors (HEMTs) on silicon carbide (SiC) substrates. Various conditions and processing methods regarding the ohmic contact and pre-metal-deposition $BCl_3$ etching processes were evaluated in terms of the device performance. In order to obtain a good ohmic contact performance, we tested a Ti/Al/Ta/Au ohmic contact metallization scheme under different rapid thermal annealing (RTA) temperature and time. A $BCl_3$-based reactive-ion etching (RIE) method was performed before the ohmic metallization, since this approach was shown to produce a better ohmic contact compared to the as-fabricated HEMTs. A HEMT with a 0.5 ${\mu}m$ gate length was fabricated using this novel manufacturing process, which exhibits a maximum drain current density of 720 mA/mm and a peak transconductance of 235 mS/mm. The X-band output power density was 6.4 W/mm with a 53% power added efficiency (PAE).

• 동력기계공학회지
• /
• 제18권4호
• /
• pp.52-59
• /
• 2014

The purpose of this study is to evaluate the performance of after-treatment equipment and thermal storage devices for a heat recovery and combustor-type $CO_2$ generator fuelled a kerosene. To reduce the levels of harmful exhaust gases produced by a $CO_2$ generator, a catalyzed particulate filter(CPF) has been selected as an after-treatment device, by considering back pressure and exhaust gas temperature. The CO conversions of the catalyzed SiC filter(full plugging) were 92%, and the concentration of PM(particulate matter) was near ambient. A thermal recovery device was used to recover 13% of the heat energy from the exhaust gas through heat exchangers installed on the exhaust line of the $CO_2$ generator. 69% of the moisture within the exhaust gases was removed by condensing water, in order to minimize excessive humidity within the greenhouse.

• 한국전기전자재료학회논문지
• /
• 제37권2호
• /
• pp.133-140
• /
• 2024

This study offers a comprehensive evaluation of the role and impact of advanced power semiconductors in solar module systems. Focusing on silicon carbide (SiC) and gallium nitride (GaN) materials, it highlights their superiority over traditional silicon in enhancing system efficiency and reliability. The research underscores the growing industry demand for high-performance semiconductors, driven by global sustainable energy goals. This shift is crucial for overcoming the limitations of conventional solar technology, paving the way for more efficient, economically viable, and environmentally sustainable solar energy solutions. The findings suggest significant potential for these advanced materials in shaping the future of solar power technology.

• 한국전기전자재료학회논문지
• /
• 제13권6호
• /
• pp.509-513
• /
• 2000

The physical and electrical characteristics of MgO and Pt thin-films on it deposited by reactive sputtering and rf magnetron sputtering respectively were analyzed with annealing temperature and time by four point probe SEM and XRD. Under annealing conditions of 100$0^{\circ}C$ and 2 hr, MgO thin-film had the properties of improving Pt adhesion to SiO$_2$and insulation without chemical reaction to Pt thin-film and the sheet resistivity and the resistivity of Pt thin-film deposited on it were 0.1288 Ω/ and 12.88 $\mu$$\Omega$.cm respectively. We made Pt resistance pattern on SiO$_2$/Si substrate by life-off method and fabricated Pt thin-film type microheater for thermal microsensors by Pt-wire Pt-paste and SOG(spin-on-glass). In the temperature range of 25~40$0^{\circ}C$ we estimated TCR(temperature coefficient of resistance) and resistance ratio of thin-film type Pt-RTD(resistance thermometer device). We obtained TCR value of 3927 ppm/$^{\circ}C$ close to the bulk Pt value. Resistance values were varied linearly within the range of the measurement temperature. The thermal characteristics of fabricated thin-films type Pt micorheater were analyzed with Pt-RTD integrated on the same substrate. The heating temperature of Pt microheater could be up to 40$0^{\circ}C$ with 1.5 watts of the heating power.

• 한국표면공학회지
• /
• 제38권4호
• /
• pp.144-149
• /
• 2005

ZnO박막을 R.F. sputtering방법으로 R.F Power와 기판온도를 공정변수로 하여 Si(100)과 $Al_2O_3(0001)$ 기판에 증착하였다. 공정변수에 따른 박막의 미세구조와 잔류응력 및 광학적 특성 등을 평가하였다. 전반적으로 R.F. Power증가에 따른 박막의 미세구조와 잔류응력 및 광학적 특성 등을 평가하였다. 전반적으로 R.F. Power증가에 따른 박막의 미세구조는 결정립이 커지면서 더 거칠어지는 것으로 나타났다. 기판온도 $800^{\cric}C$에서 증착된 박막의 경우, Si기판에 증착한 것보다 $Al_2O_3$기판에 증착된 박막의 막질이 우수한 것으로 나타났다. 박막의 잔류 응류변화는 R.F. Power 보다는 기판온도에 더 의존하는 것으로 나타났다. 대부분의 시편의 잔류응력이 공정변수인 기판온도가 증가할수록 작아지는 것으로 측정되었다. ZnO박막의 열안정성을 평가하기위해 열싸이클링을 실시하였다. 열싸이클링 결과 $Al_2O_3$(0001)기판에 증착된 박막이 Si(100)기판에 증착된 것보다 열안정성이 우수한 것으로 나타났다. PL측정의 경우, $Al_2O_3$기판에 증착된 ZnO박막이 Si기판에 증착된 것보다 UV영역의 발광이 크고 가시광선영역의 발광이 작은것으로 나타났다. 이것은 박막안의 결함이 작아서 낮은 잔류응력을 갖고 있기 때문인 것으로 생각된다.

• 한국재료학회지
• /
• 제7권3호
• /
• pp.213-217
• /
• 1997

200MHz 응향광변조기 (AOM: Acousto-Optic Modulator)는 제 2고조파(SHG: Second Harmonic Generation)녹색 레이저와 함께 DVDR(Digital Video Disk Recorder)에 적용되어 고밀도 광기록용으로 사용되었다. 이러한 고밀도 광기록 장치로써 사용되기 위해서는 고출력 레이저의 사용이 필수적이며, 레이저 빔이 통과하는 각 광학 소자들의 코팅막은 고출력 레이저 빔에 대해 높은 레이저 damage threshold를 가져야 한다. AOM의 음향공학재료로 사용되는 $TeO_{2}$단결정에 코팅막의 종류 및 증착조건을 변화시키며 E-beam 증착법으로 A/R코팅 시편을 준비하였다. 0.55W의 입력 power를 갖는Ar레이저를 사용하여 코팅의 광손상 정도를 확인하였다. $AI_{2}O_{3}$막에 비해 $ZrO_{2}$와 $SiO_{2}$막을 사용한 경우 레이저 damage threshold는 크게 향상되었다. 또한 AOM모듈을 제작 후 구동회로와 연결하여 약 20mW의 SHG power를 입력시키며 출력 power long term안정성을 측정하였다.

• 한국전기전자재료학회논문지
• /
• 제37권3호
• /
• pp.332-336
• /
• 2024

High-energy bandgap material silicon carbide (SiC) is gaining attention as a next-generation power semiconductor material, and in particular, SiC-based MOSFETs are developed as representative power semiconductors to increase the breakdown voltage (BV) of conventional planar structures. However, as the size of SJ (Super Junction) MOSFET devices decreases and the depth of pillars increases, it becomes challenging to uniformly form the doping concentration of pillars. Therefore, a structure with different doping concentrations segmented within the pillar is being researched. Using Silvaco TCAD simulation, a SJ VVD (vertical variation doping profile) MOSFET with three different doping concentrations in the pillar was studied. Simulations were conducted for the width of the pillar and the doping concentration of N-epi, revealing that as the width of the pillar increases, the depletion region widens, leading to an increase in on-specific resistance (R_on,sp) and breakdown voltage (BV). Additionally, as the doping concentration of N-epi increases, the number of carriers increases, and the depletion region narrows, resulting in a decrease in R_on,sp and BV. The optimized SJ VVD MOSFET exhibits a very high figure of merit (BFOM) of 13,400 KW/cm², indicating excellent performance characteristics and suggesting its potential as a next-generation highperformance power device suitable for practical applications.

• 전기전자학회논문지
• /
• 제19권4호
• /
• pp.491-499
• /
• 2015

Silicon Carbide(SiC)는 높은 열전도도와 넓은 밴드갭 에너지로 인해 고온과 고전압 소자로 사용하는데 큰 장점을 가지고 있는 물질이다. SiC를 이용하여 전력반도체소자를 제작할 경우, 소자가 목표 전압을 충분히 견딜 수 있도록 Edge Termination 기법을 적용하여야한다. Edge Termination 기법에는 여러 가지 방안이 제안되어왔는데, SiC 소자에 가장 적합한 기법은 Junction Termination Extension (JTE)이다. 본 논문에서는 각 JTE 구조별 도핑 농도와 Passivation Oxide Charge 변화에 따른 항복전압의 변화를 살펴보았다. 결과적으로 Single Zone JTE (SZ-JTE)는 1D 시뮬레이션 값의 98.24%, Double Zone JTE (DZ-JTE)는 99.02%, Multiple-Floating-Zone JTE (MFZ-JTE)는 98.98%, Space-Modulated JTE (SM-JTE)는 99.22%의 최대 항복전압을 나타내었고, JTE 도핑 농도 변화에 따른 최대 항복전압의 민감도는 MFZ-JTE가 가장 낮은 반면 SZ-JTE가 가장 높았다. 또한 Passivation Oxide 층의 전하로 인해 소자의 항복전압의 변화를 살펴보았는데, 이에 대한 민감도 역시 MFZ-JTE가 가장 낮았으며 SZ-JTE가 가장 높았다. 결과적으로 본 논문에서는, 짧은 JTE 길이에서 높은 도핑 농도를 필요로 하는 MFZ-JTE보다 DZ-JTE와 SM-JTE가 실제 소자 설계에 있어 가장 효과적인 JTE 기법으로 분석되었다.