• Korean Journal of Materials Research
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• v.3 no.4
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• pp.352-360
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• 1993

A nitride layer was df'posited on the thermal oxide layer by LPCVD process. ONO(oxidenitricle oxide) capacitors with various thickness of component layer wore fabricated by wet reoxidation of the nitride with and without anrwalmg treatment and their properties were investigated. As a result of observation on the refrative index and etching behavior of the ONO fIlms, the nitride layer OF 40 A thick ness was not so dense that the bottom oxide during the reoxidation process and the capability of securing the capacitance decreased. The conduction current in the ONO multl-Iayer dielctric film was reduced as the bottom(or top) oxide layer became thicker. However, in the case of oxide with thickness more than 50A, it merely plays a factor of reduction in capacitance, and the effect of barrier for hole injection was not so much increased. Annealing of the nitride laypr bpfore reoxidation did not show a grpat effects on the refractive index and capacitance of the film, however, the annealing process increased the breakdown voltage by 2${\cdot}$V.

• Journal of Korea Foundry Society
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• v.28 no.3
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• pp.124-128
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• 2008

The nitride layer was formed on Ti and Ti-10 wt.%Ta-10 wt.%Nb alloy by a plasma nitriding method. Temperature was selected as the main experimental parameter for plasma nitriding. XRD, EDX, and hardness test were employed to analyze the evolution and material properties of the layer. The SEM observation of TiN nitride layer revealed that the thickness of nitride layer tended to increase with increasing temperature. ${\delta}-TiN$, ${\varepsilon}-Ti_{2}N$ and ${\alpha}-Ti$ phases were detected by XRD analysis and the preferred orientation of TiN nitride layer was obviously observed at (220) plane with increasing temperature. From XRD analysis after step polishing the nitride specimens treated at $850^{\circ}C$, as polishing from the surface, TiN and $Ti_{2}N$ phases decreased gradually. After polishing the surface by $4{\um}m$, a small amount of $Ti_{2}N$ and ${\alpha}-Ti$ phases were observed. The adhesive strength test result indicated that adhesive strength increased with increasing temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.119-119
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• 2008

The electrical characteristics of Metal-Ferroelectric-Nitride-Oxide-Silicon (MFNOS) structure is studied and compared to the conventional Silicon-Oixde-Nitride-Oxide-Silicon (SONOS) capacitor. The ferroelectric blocking layer is SrBiNbO (SBN with Sr/Bi ratio 1-x/2+x) with the thickness of 200 nm and is fabricated by the RF sputter. The memory windows of MFNOS and SONOS capacitors with sweep voltage from +10 V to -10 V are 6.9 V and 5.9 V, respectively. The effect of ferroelectric blocking layer and charge trapping on the memory window was discussed. The retention of MFNOS capacitor also shows the 10-years and longer retention time than that of the SONOS capacitor. The better retention properties of the MFNOS capacitor may be attributed to the charge holding effect by the polarization of ferroelectric layer.

• Journal of the Korean institute of surface engineering
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• v.31 no.5
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• pp.266-277
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• 1998

The effects of $H_2S$ gas ratio, temperature and time on the case depth, hardness, and sulfide and nitride formation on the surface of sulfnitrided SCM440 steel have been studied by micro-pulse plasma technique. The thickness of compound layer of sulfide and nitride increased with the increase of time, temperautre and $H_2S$ gas ratio. But surface hardness decreased with the increase of soft sulfide layer because the hard nitride layer formed beneath the sulfide. The thickness of sulfide layer was about 10$\mu\textrm{m}$ abpve 0.0088% of $H_2S$ gas. The highest surface hardness of the compound layer was Hv835 at $530^{\circ}C$, 1hr and 0.06% of $H_2S$ gas. X-ray diffraction indicated that the surface products were $Fe_{1_x}S$, $Fe_{2.5}N$ and $Fe_4N$. It was confirmed by EPMA that sulfide only existed in the surface.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.869-876
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• 1990

Hexagonal boron nitride was synthesized from boron oxide and sodium amide in ammonia gas stream. The reaction mechanisms and characteristics of as synthesized boron nitride was investigated by means of TG, DTA, IR, XRD, SEM and PSA. The results are ; 1) hexagonal boron nitride was synthesized from reactions at temperatures above 40$0^{\circ}C$ 2) Sodium metaborate was present as by-product after reaction so that the reaction mechanism is reduced as follows : 2B2O3＋3NaNH2longrightarrowBN＋3NaBO2＋2NH3. 3) boron nitride obtained at the reaction temperature below 40$0^{\circ}C$ is found to have random layer strudcture but the structure transits to ordered layer structure rapidly with increasing reaction temperature, showing separation of (101) differaction line from (10)band in XRD pattern of the reaction product at 50$0^{\circ}C$.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.476-482
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• 1996

The multi-dielectric layer SiO$_{2}$/Si$_{3}$N$_{4}$/SiO$_{2}$(ONO) is used to improve electrical capacitance and to scale down the memory device. In this paper, improvement of the capacitance by reducing the bottom oxide thickness in the nitride deposition with load lock(L/L) vacuum system is studied. Bottom oxide thickness under the nitride layer is measured by ellipsometer both in L/L and non-L/L systems. Both results are in the range of 3-10.angs. and 10-15.angs., respectively, independent of the nitride and top oxide thickness. Effective thickness and cell capacitance for SONOS capacitor are in the range of 50-52.angs. and 35-37fF respectively in the case of nitride 70.angs. in L/L vacuum system. Compared with non-L/L system, the bottom oxide thickness in the case of L/L system decreases while cell capacitance increases about 4 fF. The results obtained in this study are also applicable to ONO scaling in the thin bottom oxide region of memory stacked capacitor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.413-416
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• 2004

In this study, zinc oxide(ZnO) having large misfit(18.2%) with sapphire was tried to be grown on very thin nitride buffer layers. For the creation of various kinds of nitride buffer layer, sapphire surface was modified by an irradiation of nitrogen ion beam with low energy generated from stationary plasma thruster(SPT) at room temperature. After the irradiation of ion beam, Al-N and Al-O-N bonding was identified to be formed as nitride buffet layers. Surface morphology was measured by AFM and then ZnO growth was followed by pulsed laser deposition(PLD). Their properties are analyzed by XRD, AFM, TEM, and PL. We observed that surface morphology was improved and deep level emission related to defects was almost vanished in PL spectra from the ZnO grown on nitride buffer layer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.725-730
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• 1996

The key process in silicon surface micromachining is the selective etching of a sacrificial layer to release the silicon microstructure. The newly developed anhydrous HF/$CH_3$OH gas phase etching of TEOS (teraethylorthosilicate) sacrificial layers onto the polysilicon and the nitride substrates was employed to release the polysilicon microstructures. A residual product after TEOS etching onto the nitride substrate was observed on the surface, since a SiOxNy layer is formed on the TEOS/nitride interface. The polysilicon microstructures are stuck to the underlying substrate because SiOxNy layer does not vaporize. We found that the only sacrificial etching without any residual product and stiction is TEOS etching onto the polysilicon substrate.

• Korean Journal of Materials Research
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• v.31 no.6
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• pp.331-338
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• 2021

Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three ㎛-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 ℃ molten metallic glass.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.84-93
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• 1999

Sliding friction and wear tests for silicon nitride(Si$_3$N$_4$) was carried out with a ball-on-disk specimen configuration. The material used in this study was HIPed silicon nitride. The tests was carried out from room temperature to 1000"I with self mated couples of slicon nitride in laboratory air. Worn surfaces were observed by SEM and debris particles from worn surfaces were analyzed degree of oxidation by XPS. XPS.