• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.354-359
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• 2011

Silicon nitride ceramics were prepared by microwave gas phase reaction sintering. By this method higher density specimens were obtained for short time and at low temperature, compared than ones by conventional pressureless sintering, even though sintering behaviors showed same trend, the relative density of sintered body inverse-exponentially increases with sintering temperature and/or holding time. And grain size of ${\beta}$-phase of the microwave sintered body is bigger than one of the conventional pressureless sintered one. Also they showed good bending strengths and thermal shock resistances.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.299-307
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• 2002

In this proposed study, a new emerging shape forming technique Direct Coagulation Casting(DCC) which enables to fabricate complex-shaped ceramic parts has been investigated using colloid surface chemistry. Various process variables affected by dispersant, coagulation agent and sintering additives, have been evaluated in order to achieve highly concentrated stabilized silicon nitride suspensions. A high solid loading of 51 vol% in the dispersed silicon nitride suspension was prepared with 1.0wt% Tetraethylammonium Hydroxide (TEAH), which obtained a stable silicon nitride suspension with sintering additives $(Al_2O_3\;and\;Y_2O_3)$ in alkaline regions. The addition of hydroxyaluminium diacetate into the suspension, which decomposed at elevated temperatures, led to coagulate of a silicon nitride suspension. In a basic medium, aluminum ions precipitated to aluminum hydroxide $(Al(OH)_3)$, leading to decreased $OH^-$ concentration and, thus, coagulated suspension.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.561-565
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• 2012

Due to their unique combination of properties, Si-based ceramics, such as silicon carbide (SiC), silicon nitride ($Si_3N_4$) and silicon oxide ($SiO_2$ as fused silica), have a range of industrial applications in fields such as the chemical industry, aluminum manufacturing, oil and gas production and solar cell production. For each materials group, examples of typical applications from various industry sectors are presented while taking into account the property fingerprint.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.832-834
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• 1992

Using the PECVD method, the silicon nitride films were deposited by changing the $SiH_4/NH_3$ gas flow ratio from 0.2 to 1.4 at an interval of 0.2, AES, FTIR, and Spectroscopic Ellipsomter were used to analyze the film composition and structure, the refractive index, and the deposition rate. Also the C-V analysis was used to estimate the memory performance in the capacitor type MNOS memory devices, which utilized native oxide as the tunneling barrier, with the silicon nitride by the above deposition conditions. As a result, it was confirmed that the performance of MNOS memory devices with PECVD silicon nitride was comparable to that with LPCVD or APCVD silion nitride.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.964-967
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• 2002

The effectiveness of silicon nitride SiNx surface passivation is investigated and quantified. This study adopted single-layer antireflection (SLAR) coating of SiNx for efficiency improvement of solar cell. The silicon nitride films were deposited by means of plasma enhanced chemical vapor deposition (PECVD) in planar coil reactor. The process gases used were pure ammonia and a mixture of silane and helium. The thickness and the refractive index on the films were measured by ellipsometry and chemical bonds were determined by using an FT-IR equipment. This films obtained were analyzed in term of hydrogen content, refractive index for gas flow ratio $(NH_3/SiH_4)$, and efficiency of solar cell. The polycrystalline silicon solar cells passivated by silicon nitride shows efficiency above 12.8%.

• Journal of the Korean Ceramic Society
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• v.44 no.10
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• pp.585-588
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• 2007

Silicon nitride films for an anti-reflection coating were deposited on silicon via RF magnetron sputtering using a $Si_3N4$ target. The best result was obtained at the sputtering condition of 340 W RF power, 5 mtorr Ar atmosphere, $100^{\circ}C$ substrate temperature. The films showed 7.9% reflectance minimum with 2.35 refractive index. 0.21 absorption coefficient at 66.6 nm thickness. The surface morphology showed a smooth and dense film with good adhesion to silicon surface.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.106-114
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• 1994

The local oxidation of silicon (LOCOS) technology, which uses a silicon nitride film as an oxidation mask and a pad oxide beween the silicon nitride and the silicon substrate, has been widely used in integrated circuits for process simplicity. But, due to long brid's beak length, there are difficulties in scabilities. Many advanced isolation techniques have been wuggested for the feduction of bird's beak length. In this paper, we presented reduced bird's beak length using the polybuffered oxide and the silicon nitride as the sidewall. Also, investigating the electrical behavior of the parasitic Al-gate MOSFET on LOCOS, we proved the validity for new isolation process.

• Journal of the Korean Ceramic Society
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• v.32 no.12
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• pp.1417-1423
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• 1995

α/β sialon based composites containing silicon nitride whisker and silicon carbide platelet were fabricated by hot pressing. Effect of the reinforcing agents on the α to β phase transformation of the sialon as well as on the mechanical properties was investigated. Silicon nitride whisker and silicon carbide platelet promoted the phse transformation. TEM/EDS analysis revealed that the grain containing the whisker had 'core-rim' structure; core being high purity Si3N4 whisker and rim being β-sialon. Flexural strength of the composite decreased with the reinforcement addition which, on the other hand, improved fracture toughness of it. High temperature strength was measured at 1300℃ to be about 130 MPa lower than that measured at RT for the whisker reinforced composites.

• Journal of the Korean Ceramic Society
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• v.23 no.5
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• pp.67-74
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• 1986

To investigate the effects of unreacted silicon on the $\alpha$/$\beta$transfornation variation of morphology and mechanical strength of Sintered Reaction Bonded Silicon Nitride the mixtures of $\alpha$-$Si_3N_4$ and Si powder and Reaction Bonded Silicon Nitride were heat treated. The heat-treatments were performed in Ar atmosphere in order to inhibit the nitridation of silicon. In the mixtures heat-trated at 1$700^{\circ}C$ the amount of $\beta$-TEX>$Si_3N_4$transformed from $\alpha$-TEX>$Si_3N_4$was sigmoidally increased and the equiaxed $\alpha$-TEX>$Si_3N_4$grains elongated with the amount of silicon and heat treating time. And large $\beta$-TEX>$Si_3N_4$grains grown into silicon were observed. On the other hand there was no change in the heat-treatment of pure $\alpha$-TEX>$Si_3N_4$In case of the heat-treatment of RBSN the same phenomena due to the silicon appearing from the decomposition of $\alpha$-Smatte and needle were observed. From the three point bending test the strength of the sintered specimens with the and without 5wt% silicon addition had 53Kg/$mm^2$ and 73Kg/$mm^2$ respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.334.2-334.2
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• 2016

Silicon nitride (SiNx:H) films are generally used as passivation layer on solar cell and they are usually made by plasma enhanced chemical vapor deposition (PECVD). In this study, we investigated the properties of silicon nitride (SiNx:H) films made by PECVD. Effects of mixture ratio of process gases with silane (SiH4) and ammonia (NH3) on the passivation qualities of silicon nitride film are evaluated. Passivation properties of SiNx:H are focused by making antireflection properties identical with thickness and refractive index controlled. The absorption coefficient of each film was evaluated by spectrometric ellipsometery and the minority carrier lifetimes were evaluated by quasi-steady-state photo-conductance (QSSPC) measurement. The optical properties were obtained by UV-visible spectrophotometer. The interface properties were measured by capacitance-voltage (C-V) measurement and the film components were identified by Fourier transform infrared spectroscopy (FT-IR) and Rutherford backscattering spectroscopy detection (RBS) - elastic recoil detection (ERD).