• 한국세라믹학회지
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• 제51권3호
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• pp.197-200
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• 2014

We investigated the influence of blistering on $Al_2O_3$/SiON stacks and $Al_2O_3$/SiNx:H stacks passivation layers. $Al_2O_3$ film provides outstanding Si surface passivation quality. $Al_2O_3$ film as the rear passivation layer of a p-type Si solar cell is usually stacked with a capping layer, such as $SiO_2$, SiNx, and SiON films. These capping layers protect the thin $Al_2O_3$ layer from an Al electrode during the annealing process. We compared $Al_2O_3$/SiON stacks and $Al_2O_3$/SiNx:H stacks through surface morphology and minority carrier lifetime after annealing processes at $450^{\circ}C$ and $850^{\circ}C$. As a result, the $Al_2O_3$/SiON stacks were observed to produce less blister phenomenon than $Al_2O_3$/SiNx:H stacks. This can be explained by the differences in the H species content. In the process of depositing SiNx film, the rich H species in $NH_3$ source are diffused to the $Al_2O_3$ film. On the other hand, less hydrogen diffusion occurs in SiON film as it contains less H species than SiNx film. This blister phenomenon leads to an increase insurface defect density. Consequently, the $Al_2O_3$/SiON stacks had a higher minority carrier lifetime than the $Al_2O_3$/SiNx:H stacks.

• 한국표면공학회지
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• 제51권2호
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• pp.110-115
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• 2018

The Na low temperature gettering in $SiO_2/PSG/SiO_2/Al-1%Si$ and $SiO_2/TEOS/SiO_2/Al-1%Si$ multilevel thin films was investigated using dynamic SIMS(secondary ion mass spectrometry) analysis. DC magnetron sputter, APCVD and PECVD techniques were utilized for the deposition of Al-1%Si thin films, $SiO_2/PSG/SiO_2$ and $SiO_2/TEOS/SiO_2$ passivations, respectively. Heat treatment was carried out at $300^{\circ}C$ for 5 h in air. SIMS depth profiling was used to determine the distribution of Na, Al, Si and other elements throughout the $SiO_2/PSG/SiO_2/Al-1%Si$ and $SiO_2/TEOS/SiO_2/Al-1%Si$ multilevel thin films. XPS was used to analyze chemical states of Si and O elements in $SiO_2$ passivation layers. Na peaks were observed throughout the $PSG/SiO_2$ and $TEOS/SiO_2$ passivation layers on the Al-1%Si thin films and especially at the interfaces. Na low temperature gettering in $SiO_2/PSG/SiO_2/Al-1%Si$ and $SiO_2/TEOS/SiO_2/Al-1%Si$ multilevel thin films is considered to be caused by a segregation type of gettering.

• 한국세라믹학회지
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• 제34권5호
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• pp.535-543
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• 1997

The surface of SiC particles were partially oxidized to produce SiO2 layers on the SiC particles to prepare Al2O3/SiC composite by formation of mullite bonds between the grains of Al2O3 and SiC during sintering at 1$600^{\circ}C$. This process is considered to enable the sintering of Al2O3/SiC composite at lower temperature and also to relieve the stress, produced by thermal expansion mismatch between Al2O3 and SiC. In fact, Al2O3/SiC composite prepared by oxidation of SiC was observed to be more effectively sintered and densified at lower temperature. Maximum density, flexural strength and microhardness were obtained with 5.65 vol% of mullite content in Al2O3/SiC composite.

• 마이크로전자및패키징학회지
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• 제7권2호
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• pp.37-42
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• 2000

저유전상수 폴리머와 $SiO_2$위에 형성된 Al/Ti박막의 우선방위에 대해 비교하였다. DC 마그네트론 스퍼터를 이용하여 50 nm 두께의 Ti과 500 nm의 Al-1%Si-0.5%Cu(wt%) 합금 박막을 저유전상수 폴리머와 $SiO_2$기판위에 증착하였다. Al의 우선방위는 XRD $\theta$-2$\theta$와 rocking curve로 측정하였고, Al/Ti박막의 미세조직은 투과전자현미경 (TEM)으로 관찰하였다. 저 유전상수 폴리머 위에 증착된 Al/Ti박막은 $SiO_2$위에 증착된 것보다 낮은 우선방위를 가졌다. 단면 TEM으로 Ti을 관찰한 결과, $SiO_2$위의 Ti의 결정립은 기판에 수직하게 성장하였으나 저유전상수 폴리머 위의 Ti 결정립은 등축정으로 성장하였으며, 저유전상수 폴리머위의 Al/Ti박막이 낮은 우선방위를 갖는 이유는 Ti 미세조직 때문이었다.

• 한국세라믹학회지
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• 제27권5호
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• pp.583-588
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• 1990

Glass films in the binary system B2O3-SiO2 and Al2O3-SiO2 were prepared on soda-lime-silica slide glass by the dip-coating technique from TEOS and boric acid or aluminum nitrate. Thickness of the films varying with viscosity and withdrawal speed were measured and effect of composition and firing temperature on the properties such as transmittance and refractive index were investigated. nM2O3.(100-n)SiO2(M=B or Al) films containing up to 20mol% B2O3 and 40mol% Al2O3 were transparent. Maximum transmittance at visible range were obtained for the sample containing 15mol% Ba2O3 and 32.5mol% Al2O3 and heat-treated at 50$0^{\circ}C$, respectively. Refractive index of the film containing 15mol% B2O3 was mininum in the B2O3-SiO2 binary system and minimal refractive index was appeared at the film containing 32.5mol% Al2O3. In IP spectra, addition of B2O3 were increased absorption peak intensity of B-O and Si-O-B bond and addition of Al2O3 were decreased absorption peak intensity of Si-O bond, respectively.

• 한국세라믹학회지
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• 제34권4호
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• pp.406-412
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• 1997

Al2O3/SiC hybrid-composite has been fabricated by the conventional powder process. The addition of $\alpha$-Al2O3 as seed particles in the transformation of ${\gamma}$-Al2O3 to $\alpha$-Al2O3 provided a homogeneity of the microstructure. The grain growth of Al2O3 are significantly surpressed by the addition of nano-size SiC particles. Dislocation were produced due to the difference of thermal expansion coefficient between Al2O3 and SiC and piled up on SiC particles in Al2O3 matrix, resulting in transgranular fracture. The high fracture strength of the composite was contributed to the grain refinement and the transgranular fracture mode. The addition of SiC platelets to Al2O3/SiC nano-composite decreased the fracture strength, but increased the fracture toughness. Coated SiC platelets with nitrides such as BN and Si3N4 enhanced fracture toughness much more than non-coated SiC platelets by enhancing crack deflection.

• 한국세라믹학회지
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• 제29권3호
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• pp.223-231
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• 1992

CaO and ZnO were added to Al2O3-SiO2 binary system respectively as flux, then ZrO2 and TiO2 were applied as nucleating agent to these CaO-Al2O3-SiO2 and ZnO-Al2O3-SiO2 ternary system glass. The transparency could not be kept in CaO-Al2O3-SiO2 system glass, whereas the transparent glass-ceramics were prepared in ZnO-Al2O3-SiO2 system glass containing ZrO2 as the nucleating agent. At this time the optimum heating temperatures for the nucleation and the crystal growth were 78$0^{\circ}C$ and 97$0^{\circ}C$. The sizes of the precipitated crystals in the transparent glass-ceramics were below 0.1 ${\mu}{\textrm}{m}$, and their light transmissibilities were more than 80%.

• 한국세라믹학회지
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• 제43권10호
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• pp.595-600
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• 2006

The preparation of $\beta$-SiAlON powder by SHS in the system of $Si-Al-SiO_2-NH_4F(\beta-Si_3N_4)$ was investigated in this study. In the preparation of SiAlON powder, the effect of gas pressure, compositions such as Si, $NH_4F$, \beta-Si_3N_4$ and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $\beta$-SiAlON was $3Si+Al+2SiO_2+NH_4F$. The $\beta$-SiAlON powder synthesized in this condition was a single phase $\beta$-SiAlON with a rod like morphology.

• 한국세라믹학회지
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• 제30권9호
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• pp.731-739
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• 1993

R-curve measurements were performed on Al2O3(matrix)-ZrO2-SiC whisker composite and Al2O3-ZrO2, Al2O3-SiC whisker composites in the favor of comparing the effect of ZrO2 and SiC whisker, as a second phase, to Al2O3 matrix. Al2O3-SiC whisker and Al2O3-ZrO2-SiC whisker were fabricated by hot pressing at 1$700^{\circ}C$, 15MPa and Al2O3-ZrO2 by pressureless sintering at 1$600^{\circ}C$. A controlled flaw/strength technique was utilized to determine fracture resistance as a function of crack extension and R-curve behaviour was determined from the relationship which is KR=K0(Δa)m. R-curveresults were KR=6.173$\times$Δa0.031 for Al2O3-ZrO2, KR=18.796$\times$Δa0.172 for Al2O3-SiC whisker and KR=11.96$\times$Δa0.110 for Al2O3-ZrO2-SiC whisker composite. From the analysis of R-curve and expeirmental data above three composites, it is found that R-curve behaviour of Al2O3-ZrO2-SiC whisker composite was dominated initially by the strengthening effect of ZrO2 and after, some extended crack were influenced by the effect of SiC whisker. Analysis of SEM and X-ray data revealed that whisker bridging in the crack wake and whisker pull-out mechanisms were the main mechanism for the R-curve behaviour.

• 한국세라믹학회지
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• 제33권11호
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• pp.1209-1216
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• 1996

MoSi2-Al2O3 composites were prepared by thermal explosion mode of self-propagating high temperature syn-thesis (SHS) using element powders of MoO3 Mo Si and Al. The combustion products of MoSi2 which have 10, 20, 30 and 40 wt% Al2O3 showed the molten state in the range of Mo to MoO3 6:1-9.5:1, 2:1-8:1, 1:1-5:1, and 1:1-3:1 (molar ratio) respectively. The combustion products which made least seperation the molten phase from the slag phase were in Mo/MoO3=9, 5:1, 8:1, 5:1 and 3:1 (molar ratio) respectively. Particles size of MoSi2 and Al2O3 in the combustion product were decreased as the molar ratio of Mo to MoO3 increase. By XRD analysis only MoSi2 and $\alpha$-Al2O3 peaks were identified in the combusion products, In case of MoSi2 containing 20wt% Al2O3 5.1wt% Al existed into MoSi2 grains and 30.7wt% Si and 7.7wt% Mo existed into Al2O3 grains. The relative density of MoSi2 containing 10, 20, 30 and 40 wt% Al2O3 were 82.7, 85.2, and 81.9% respectively. The fracture strength of MoSi2-Al2O3 composites increased with increasing Al2O3 and that of MoSi2-20wt% Al2O3 composite was 195 MPa.