• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.216-216
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• 2012

The purpose of this work is to investigate a back surface field (BSF) on variety wafer resistivity for industrial crystalline silicon solar cells. As pointed out in this manuscript, doping a crucible grown Cz Si ingot with Ga offers a sure way of eliminating the light induced degradation (LID) because the LID defect is composed of B and O complex. However, the low segregation coefficient of Ga in Si causes a much wider resistivity variation along the Ga doped Cz Si ingot. Because of the resistivity variation the Cz Si wafer from different locations has different performance as know. In the light of B doped wafer, we made wider resistivity in Si ingot; we investigated the how resistivities work on the solar cells performance as a BSF quality.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.699-702
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• 1997

The cross sectional image of thin oxide failure of MOS device could be observed by Emission Microscope and Focused Ion Beam at the weak point. The oxide failures in low electric field was associated with the presence of a particle or abnormal pattern. The failures occuring at medium field are related to a pit of Si substrate. The pits could be originated from the microdefects of Cz Si wafer.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.3
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• pp.89-95
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• 2001

The CZ-silicon crystal was annealed at $1350^{\circ}C$ to dissolve the vacancy type grown-in defects. A this temperature, the equilibrium concentration of the oxygen in the silicon crystal is around $1.7{\times}10^{18}$ which induces the oxygen undersaturation in the silicon crystal. This situation results in the faster dissolution of the grown-in defects in the bulk of the silicon wafer than near the surface. This indicates the possibility that the presence of the higher concentration of silicon interstitial hinders the dissolution of the grown-in defects, which were known to compose of the vacancy clusters with surrounding silicon oxide film. This expectation was confirmed by the observation that the slower dissolution of the grown-in defects near the surface of the silicon wafer in the oxygen atmosphere than in the argon atmosphere. This result is quite opposite to the previous argument hat presence of the excess silicon interstitial leads to faster dissolution of the vacancy type defects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.246-251
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• 2014

Recent studies have shown methods of improving solar cell efficiency. Especially on single crystalline silicon wafer which is high-efficiency solar cell material that has been widely studied. Interstitial oxygen (Oi) is the main impurity in the Czochralski (Cz) growing method, and excess of this can form precipitates during cell fabrication. We have demonstrated the effect of Oi impurity and oxygen precipitation concentration of the wafer on Cz-silicon solar cell efficiency. The result showed a decrease in cell efficiency as Oi and oxygen precipitation increase. Moreover, we have found that the critical point of [Oi] to bring higher cell efficiency is at 14.5 ppma in non-existent Bulk Micro Defect (BMD).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.6
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• pp.272-278
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• 2013

In this study, a c-axis displacement and an internal stress of the sapphire crystal of 300 mm length have been analyzed numerically and the crystal length having no sub-grain defects have been predicted. The hot zone structures were modified with the crucible geometry change and the additional insulation layer installed above the crucible. The simulation results show that the c-axis displacement difference between the original hot zone and others originated from the sub-grain defect formations in the sapphire ingot. When the crystal grown by CZ (Czochralski) grower using the modified hot zone, the crystal length having no sub-grain defects was increased about 57 mm maximum than the original one. When the simulation results compared with the experimental one, the predicted crystal length having no sub-grain defects were well corresponded with the experiment one in c-axis wafer of the 300 mm sapphire ingot. Therefore the sapphire crystal of 250 mm length having no sub-grain defects was successfully grown by CZ process.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.495-501
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• 1991

This study is intended to make defect-free region, denuded zone at the silicon wafer surface for semiconductor device substrates. In this experiment, initial oxygen concentration of starting material CZ-grown silicon wafer, various heat treatment combinations, denuding ambient and the amounts of oxygen reduction were measured, and then denuded zone (DZ) formation and depth were investigated. In Low/High anneal (DZ formation could be achieved), the optimum temperature for Low anneal was 700$^{\circ}C$∼750$^{\circ}C$. In case of High anneal, with the time increased, DZ depth was increased at 1000$^{\circ}C$, 1150$^{\circ}C$ respectively, but on the contrary, DZ depth was decreased at low temperature 900$^{\circ}C$. As well, out-diffusion time below 2 hours was unsuitable for effective Gettering technique even though the temperature was high, and DZ formation could be achieved when initial oxygen concentration was only above 14 ppm in silicon wafer.

• Korean Journal of Materials Research
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• v.11 no.1
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• pp.55-60
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• 2001

The effect of high energy B ion implantation and initial oxygen concentration upon defect formation and gettering of metallic impurities in Czochralski silicon wafer has been studied by applying DLTS( Deep Level Transient Spectroscopy), SIMS(Secondary ton Mass Spectroscopy), BMD (Bulk Micro-Defect) analysis and TEM(Transmission Electron Microscopy). DLTS results show the signal of the deep levels not only in as-implanted samples but also in low and high temperature annealed samples. Vacancy-related deep levels in as- implanted samples were changed to metallic impurities-related deep levels with increase of annealing temperature. In the case of high temperature anneal, by showing the lower deep level concentration with increase of initial oxygen concentration, high initial oxygen concentration seems to be more effective compared with the lower initial oxygen one.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.66-73
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• 1991

During the growth of macroscopically dislocation-free Czochralski silicon crystal, micro precipitates causing stacking faults in the silicon wafer during the oxidation are formed Thermal history the cryscausing acquire during the growth process is known to be a key factor determining the nucleation of this micro precipitates. In this article, various mechanisms suggested on the formation of microdefects in the silicon crystal are reviewed to secure the nucleation mechanism of the micro precipitates causing OSF whose pattern is normally ring or annular in CZ silicon crytal. B-defects which are known as vacancy clustering are considered to be the heterogeneous nucleation sites for the micro precipitates causing OSF in the CZ silicon crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.42-47
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• 2000

The surface structure and the crystalline features in the near surface region have been investigated for CZ(Czochralski) grown Si wafers. Si wafers were annealed by RTA (Rapid Thermal Annealing) method in H$_2$ambient after mirror polished process. The densities of COPs (Crystal Originated Particles) after RTA process were remarkably decreased at the surface and in the region of 5um depth from the surface as well. terrace type surface structure which was formed by etching and re-arrangement of Si atoms during $H_2$annealing process also has been observed.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.29-38
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• 1998

In this paper, we have induced a model for the growth and dissolution of oxygen precipitates which is generated during arbitrary thermal treatments or VLSI processes in CZ-grown silicon. Based on diffusion-limited growth law and detailed balance equilibrium theory, growth and dissolution rates are induced and inserted into a set of chemical rate equations and a Fokker-Planck equation. Then this is solved by numerical analysis. And because phenomenon at the silicon surface must be considered differently in various annealing conditions, in particular in $O_2$ ambient we have considered the growth model of SiO$_2$ at the surface of silicon wafer and the enhancement of oxygen solubility. By this method, oxygen depth profile and density distribution of oxygen precipitates are calculated more accurately than the other simulation results.