• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.691-694
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• 2003

We report a quantum wavepacket study on the characteristic bimodal translational energy distribution of photostimulated desorbed Xe from an oxidized silicon (001) surface observed by Watanabe and Matsumoto, Faraday Discuss. 117 (2000) 203. We have simulated the theoretical translational energy distributions based on wavepacket calculations with a sudden transition and averaging model to reproduce the experiment. We discuss the desorption mechanism and suggest a very strong position dependence of the deexcitation processes for Xe/oxidized Si(001).

• 대한전기학회논문지
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• 제45권1호
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• pp.93-99
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• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.122.1-122.1
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• 2011

Phosphorus is known to pile-up at the silicon surface when it is thermally oxidized. A thin layer, about 40nm thick from the silicon surface, is created containing more phosphorus than the bulk of the emitter. This layer has a gaussian profile with the peak at the surface of the silicon. In this study the pile-up effect was studied if this layer can act as a front surface field for solar cells. The effect was also tested if its high dose of phosphorus at the silicon surface can lower the contact resistance with the front metal contact. P-type wafers were first doped with phosphorus to create an n-type emitter. The doping was done using either a furnace or ion implantation. The wafers were then oxidized using dry thermal oxidation. The effect of the pile-up as a front surface field was checked by measuring the minority carrier lifetime using a QSSPC. The contact resistance of the wafers were also measured to see if the pile-up effect can lower the series resistance.

• 한국세라믹학회지
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• 제33권5호
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• pp.572-582
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• 1996

전류밀도, 70mA/cm2와 전류인가시간, 5초, 10초 조건의 양극반응으로 다공성 실리콘을 제작하여 800~110$0^{\circ}C$에서 열산화시킨 후 AI 전극을 증착시켜 만든 MOS(Metal Oxide Semiconductor) 구조의 C-V(Capacilance-Voltage) 특성을 조사하였다. 800, 90$0^{\circ}C$의 저온과 20~30분 이내의 단시간 산화에서는 산화막의 유전상수가 보통의 열산화막보다 크게 나타나고, 산화온도가 110$0^{\circ}C$의 고온과 60분 이상의 장시간 산화의 경우에는 3.9에 근접한 값을 갖는다. 이는 다공성 실리콘 산화막내에 존재하는 산화되지 않은 silicon들에 의한 효과와 표면적 증가에 의한 정전용량의 증가 효과가 복합적으로 작용하는 것이 그 원인이라 생각된다.

• 한국표면공학회지
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• 제22권4호
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• pp.215-220
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• 1989

Silicon Nitride whose thickness is about $100\AA$by the ellipsometer was successfully formed by the Plasma reaction. Nitrogen Plasma was formed by applying the 200KHz, 500Watt power between the two electroes and nitridation of silicon was carried out directly on the top of the silicon wafer. Thus Silicon Nitride formed was oxidized to from oxynitrides and their electrical characterlstice were analyzed by measuring I-V curves and capacitances. Through ESCA depth profiles, the chemical composition changes before and after the oxidation wers analyzed.

• 한국세라믹학회지
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• 제31권12호
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• pp.1588-1598
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• 1994

The SiC/MoSi2 composite materials were fabricated by infiltrating the mixture of molybdenum disilicide and metal silicon(MoSi2+Si=100) to a porous compact of silicon carbide and graphite under the vacuum atmosphere of 10-1 torr. The specimen were oxidized in dry air under 1 atm at 130$0^{\circ}C$~150$0^{\circ}C$ for 240 hours. The oxidation behavior was evaluated by the weight gain and loss per unit area of the oxidized samples. Also, SEM and XRD analysis of the oxidized surface of the samples were carried out. With increasing the MoSi2 content and oxidation temperature, the passive oxidation was found. The trend of weight gain of all samples was followed the parabolic rate law with the formation of a protective layer of cristobalite on the surface.

• Corrosion Science and Technology
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• 제4권4호
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• pp.136-139
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• 2005

The effect of oxidation and hot corrosion on the solid particle erosion was investigated for hot-pressed silicon nitride using as-polished, pre-oxidized and pre-corroded specimens by molten sodium sulfates. Erosion tests were performed at 22, 500 and $900^{\circ}C$ using angular silicon carbide particles of mean diameter $100{\mu}m$. Experimental results show that solid particle erosion rate of silicon nitride increases with increasing temperature for as-polished or pre-oxidized specimens in consistent with the prediction of a theoretical model. Erosion rate of pre-oxidized specimens is lower than that of as-polished specimens at $22^{\circ}C$, but it is higher at $900^{\circ}C$. Lower erosion rate at $22^{\circ}C$ in the pre-oxidized specimens is attributed due to the blunting of surface flaws, and the higher erosion rate at $900^{\circ}C$ is due to brittle lateral cracking. Erosion rate of pre-corroded specimens decreases with increasing temperature. Less erosion at $900^{\circ}C$ than at $22^{\circ}C$ is associated with the liquid corrosion products sealing off pores at $900^{\circ}C$ and the absence of inter-granular crack propagation observed at $22^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1066-1068
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• 1995

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical oxidation and current density. The humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by increasing a porosity of PSL.

• 대한전자공학회논문지SD
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• 제40권8호
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• pp.560-564
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• 2003

본 논문에서는 RTP(rapid thermal process)를 이용한 새로운 산화방법을 고안했으며, 이는 짧은 시간에 다공질 실리콘을 산화시킴으로써 이 기술은 여타 방법에 비해 경제적이고 간편한 방법으로 짧은 시간에 두꺼운 산화막을 성장시킬 수 있는 장점을 가지고 있다. 먼저, 양극반응을 통해 PSL(porous silicon layer)을 형성한 후 이를 저온 산화시킨 후에 급속 열처리 산화공정(RTO: rapid thermal oxidation)를 이용해서 OPSL(oxidized porous silicon layer)을 제조하고, 그 물성 및 전기적 특성을 조사하여, 열 산화로 제작된 OPSL과 그 특성을 비교하였다. 시편의 절연 파괴전압은 약 3.9 MV/cm의 값을 보여 벌크 산화막보다는 적은 값이지만 절연 재료로서는 충분한 값이고, 누설전류는 0 ∼ 50 V의 인가 전압에서 100 ∼ 500 ㎀의 값을 보였다. 그리고, XPS 결과는 RTO 공정 추가가 저온 산화막의 완전 산화에 크게 기여함을 확인하였으며, 저온 산화막의 표면 및 내부에서도 산화반응이 완전하게 이루어졌음을 확인하였다. 이 결과로부터 저온 OPSL을 제조할 때, RTO 공정이 OPSL의 산화 및 치밀화(densification)의 증가에 크게 기여함을 알 수 있었다. 따라서, 이의 방법으로 제조된 OPSL은 저온을 요구하는 공정에서 소자의 절연막, 전기적인 분리층 그리고 실리콘 고주파용 기판 등으로 활용될 수 있을 것으로 보인다.

• 한국표면공학회지
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• 제43권1호
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• pp.36-40
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• 2010

The SiO vapor that was generated from a mixture of Si and $SiO_2$ was reacted at $1350^{\circ}C$ for 2 h under vacuum with carbon nanofibers to produce SiC nanofibers having an average diameter of 100~200 nm. In order to understand the gas corrosion behavior, SiC nanofibers were exposed to air up to $1000^{\circ}C$. SiC oxidized to amorphous $SiO_2$, but its oxidation resistance was inferior unlike bulk SiC, because of high surface area of nanofibers. When SiC nanofibers were exposed to Ar-1% $SO_2$ atmosphere, SiC oxidized to amorphous $SiO_2$, without forming $SiS_2$, owing to the thermodynamic stability of $SiO_2$.