• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.120-123
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• 2005

The 5 mol% ZnO doped $LiNbO_3$ film and the 2 mol% MgO doped $LiNbO_3$ film were grown on the $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method with $Li_2CO_3-V_2O_5$ flux system. The crytsallinity and the lattice mismatch between $Zn:LiNbO_3$, film and $Mg:LiNbO_3$, film were analyzed by x-ray rocking curve (XRC). In addition, the ZnO and MgO distribution in the cross-section of the multilayer thin films was observed using electron probe micro analyzer (EPMA).

• Journal of the Korean Magnetics Society
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• v.22 no.5
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• pp.162-166
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• 2012

V-I characteristics of Fe(100)/MgO(100)/Cu-phthalocyanine (CuPc)/Co hybrid magnetic tunnel junctions were investigated at different temperatures. Fe(100) and Co ferromagnetic layers were separated by an organic-inorganic hybrid barrier consisting of different thickness of CuPc thin film grown on a 2 nm thick epitaxial MgO(100) layer. As the CuPc thickness increases from 0 to 10 nm, a bistable switching behavior due to strong charging effects was observed, while a very large magenetoresistance was shown at 77 K for the junctions without the CuPc barrier. This switching behavior decreases with the increase in temperature, and finally disappears beyond 240 K. In this work, high-potential future applications of the MgO(100)/CuPc bilayer were discussed for hybrid spintronic devices as well as polymer random access memories (PoRAMs).

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.34-40
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• 1985

Characteristics of GaAE epilayers grown on (100) CaAs wa(tors by molecular beam epitaxy (MBE) under various single crystal growing conditions were investigated. In fabrica-ting GaAs, epilayer by MBE, the most important factors are a substrate temperature(ts) and a flux density ratio (As/Ga). In this experiment, the substrate temperature was varied in the range of 48$0^{\circ}C$ to $650^{\circ}C$ and As and Ga cell temperatures were varied in the range of 218$^{\circ}C$ to 256$^{\circ}C$ and 876$^{\circ}C$ to 98$0^{\circ}C$, respectively. At the substrate temperature of 54$0^{\circ}C$, As cell temperature of 23$0^{\circ}C$, and Ga cell temperature of 91$0^{\circ}C$, the As/Ga ratio was 5"10, the surface morphology was most smooth . Investigation of As-stabilized surface by RHEED and of depth profile by SIM5 showed that As is less stable than Ga. Also, X-ray diffraction measurement revealed that single crystals of (400) and (200) were formed at the both sub-strate temperatures of 52$0^{\circ}C$ and 54$0^{\circ}C$.TEX>.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.142-142
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• 2011

Epitaxial $CuCrO_2$ thin films have been grown on single crystal substrate of c-plane $Al_2O_3$, $SrTiO_3$, YSZ and Quarts by laser ablation of a $CuCrO_2$ target using 266nm radiation from a Nd:YAG laser. X-ray measurements indicate that the $CuCrO_2$ grows epitaxially on all substrate, with its orientation dependent on the kinds of substrates. Most of the layer were polycrystalline with (001), (015) and random as the dominant surface orientation on c-plane YSZ, $SrTiO_3$ and quarts substrate, respectively. (001) orientated $CuCrO_2$ grows on C-plane $Al_2O_3$ and YSZ substrate, (015) orientated $CuCrO_2$ films are found on c-plane $SrTiO_3$ substrate and random orientated $CuCrO_2$ films grows on quarts substrate. These data are compared with the in-plane orientation and the mismatch of the $CuCrO_2$ and each substrate lattices in an attempt to relate the preferred orientation to the plane of the sapphire on which it is grown. Further characterization show that the grain size of the films increases for a substrate temperature increase, whereas the electrical properties of $CuCrO_2$ thin films depend upon their crystalline orientation.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.19-27
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• 1993

Capacitive pressure sensor for low pressure measurements has been fabricated by using $n^{+}$ epitaxial layer electrochemical etching stop and glass-to-silicon electrostatic bonding technique. The sensor had hybrid configuration of a sensor chip, which consists of sensor capacitor and reference capacitor, and two output signal detection IC chips. A fabricated sensor, with a $1.0{\times}1.0 mm^{2}$ square size and a $10{\mu}m$ thick flat diaphragm, showed a 7.1 pF zero pressure capacitance, and 5.2 % F.S, sensitivity in 10 KPa pressure range. By using a capacitance to voltage converter, the thermal zero shift of 0.051 %F.S./$^{\circ}C$ and the thermal sensitivity shift of 0.12 %F.S./$^{\circ}C$ for temperature range of $5{\sim}45^{\circ}C$ were obtained.

• Journal of the Korean Vacuum Society
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• v.14 no.4
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• pp.222-228
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• 2005

Undoped GaN epitaxial layer was grown on c-plane sapphire substrate by a two-step growth with metalorganic chemical vapor deposition(MOCVD). We have investigated the effects of the variation of final growth temperature on surface morphology, roughness, crystal quality, optical property, and electrical property In a horizontal MOCVD reactor, the film was grown at 300 Tow low-pressure with a fixed nucleation temperature of $500^{\circ}C$, varing the final growth temperature from $850\~1050^{\circ}C$ . The undoped GaN epilayers were characterized by atomic force microscopy, high-resolution x-ray diffractometer, photoluminescence, and Hall effect measurement.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.25-29
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• 2021

This paper demonstrates the utility of the Ni-Pd and carbon-nanotube (Ni-Pd-CNT)-based nanoalloy to improve the α-Ga₂O₃ crystal quality using the halide-vapor-phase epitaxy (HVPE) method. As result, the overall thickness of the α-Ga₂O₃ epitaxial layer increased from a Ni electroless plating time of 40 s to 11 ㎛ after growth. In addition, the surface morphologies of the α-Ga₂O₃ epilayers remained flat and crack-free. The full-width half-maximum results of the X-ray diffraction analysis revealed that the ($10{\bar{1}}4$) diffraction patterns decreased with increasing nominal thickness.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.134-138
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• 2023

This study focuses on the analysis of the results of computational fluid dynamics simulations of mist-chemical vapor deposition for the growth of an epitaxial wafer in power semiconductor technology using artificial intelligence techniques. The conventional approach of predicting the uniformity of the deposited layer using computational fluid dynamics and design of experimental takes considerable time. To overcome this, artificial intelligence method, which is widely used for optimization, automation, and prediction in various fields, was utilized to analyze the computational fluid dynamics simulation results. The computational fluid dynamics simulation results were analyzed using a supervised deep neural network model for regression analysis. The predicted results were evaluated quantitatively using Euclidean distance calculations. And the Bayesian optimization was used to derive the optimal condition, which results obtained through deep neural network training showed a discrepancy of approximately 4% when compared to the results obtained through computational fluid dynamics analysis. resulted in an increase of 146.2% compared to the previous computational fluid dynamics simulation results. These results are expected to have practical applications in various fields.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.10
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• pp.671-677
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• 2001

A RuO$_2$ Schottky photo-detector was designed and fabricated with GaN layers on the sapphire substrate. For good absorption of UV light, an epitaxial structure with undoped GaN(0.5 ${\mu}{\textrm}{m}$)/n￣-GaN(0.1${\mu}{\textrm}{m}$)/n＋-GaN(1.5${\mu}{\textrm}{m}$) was grown by MOCVD. The structure had the carrier concentrations of 3.8$\times$10$^{18}$ cm￣$^3$, the mobility of 283$\textrm{cm}^2$/V.s. After ECR etching process for mesa structure with the diameter of about 500${\mu}{\textrm}{m}$, Al ohmic contact was formed on GaN layer. After proper passivation between the contacts with Si$_3$/N$_4$, was formed on undoped GaN layer. The fabricated Schottky diode had a specific contact resistance of 1.15$\times$10$^{-5}$ ［$\Omega$.$\textrm{cm}^2$］. It has a low leakage current of 305 pA at -5 V, which was attributed by stable characteristics of RuO$_2$ Schottky contact. In optical measurement, it showed the high UV to visible extinction ratio of 10$^{5}$ and very high responsivity of 0.23 A/W at the wavelength of 365nm.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.183-194
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• 1992

Some silicon micromechanical structures useful in sensors and actuators have been fabricated by electropolishing or porous silicon formation technique by anodic reaction in HF solution. The microstructures were lightly doped single crystal silicon and the formation was isotropic independent of crystal directions. Porous silicon layer(PSL) was formed selectively in $n^{+}$ region of $n^{+}/n$ silicon structure by anodic reaction in concentrated HF(20-48%) solution. Characteristics of the formed PSL were investigated along with change of the reaction voltage, HF concentration and the reaction time. PSL was formed only in $n^{+}$ region. The porosity of the PSL was decreased with the increase of HF concentration and independent of reaction voltage. For the case of $n/n^{+}/n$ structures, the etched surface of silicon was fairly smooth and a cusp was not found. The thickness of the microstructures was the same as that of the epitaxial n-Si layer and good uniformity. We have fabricated acceleration sensors by anodic reaction in HF solution(5 wt%) and planar technology. The process was compatible with conventional It fabrication technique. Various micromechanical structures, such as rotors of motor, gears and linear actuator, were also fabricated by the technique and examined by SEM photographs.