• Journal of Surface Science and Engineering
• /
• v.34 no.6
• /
• pp.537-544
• /
• 2001

In the present study, tin-zinc alloys were coated on a cold-rolled steel sheet with variations of electrolyte concentration, additives quantity and current density employing the Hull cell and circulation cell simulator. With an addition of additives of 2m1/L, tin-zinc deposits containing 10 to 40 percent Zn revealed a good surface appearance with weak acidic electrolytes. The organic additives suppressed the Sn deposition rate and thus increased the zinc contents in tin-zinc coating layers. The zinc contents in the tin-zinc coating layers depended almost linearly on the concentrations of metal ions of tin and zinc. Temperature of the electrolyte affected the composition tin-zinc coating layer. However, the concentration of complexants revealed little effectiveness. The surface morphology of tin-zinc coating showed dense tin and zinc phases with fine equiaxed grains with the high current density.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.170-170
• /
• 2003

We have implanted on sapphire substrate with various ions and investigated the properties of GaN epilayers grown on implanted sapphire substrate by metal organic chemical vapor deposition (MOCVD). Sapphire is typical substrate for GaN epilayers. However, there are many problems such as lattice mismatch and thermal coefficient difference between sapphire substrate and GaN. The ion implanted substrate's surface had decreased internal tree energies during the growth of the GaN epilayer, md the misfit strain was relieved through the formation of an AlN phase on the ions implanted sapphire(0001) substrates. [1] The crystal and optical properties of GaN epilayer grown in ions implanted sapphire(0001) substrate were improved.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.163-163
• /
• 2003

TiN barrier막 위에 metal organic chemical deposition(MOCVD)법으로 RuO$_2$ 를 증착시 TiN막 표면을 세정처리하지 않을 경우 RuO$_2$의 핵생성이 어렵고, 그로 인해 RuO$_2$ 연속막이 형성되기 힘들다. 그러므로 RuO$_2$의 핵생성을 향상시키기 위해 TiN막에 대한 전처리 세정이 필수적이다. TiN막의 전처리 세정방법으로 ECR plasma 세정법을 사용하였으며, $O_2$ plasma와 H$_2$ plasma 그리고 Ai plasma를 이용해 각각의 exposure time을 변화시키며 전처리 세정을 실시하였다. H$_2$ plasma와Ar plasma의 exposure time이 증가됨에 따라 RuO$_2$의 핵생성이 향상되었다. 본 연구에서는 scanning electron microscopy(SEM), Auger electron emission spectrometry(AES), Atomic Force Microscope(AFM), X-ray diffraction (XRD) 등의 분석을 통해 TiN막 표면에 대한 ECR plasma 전처리 세정 이 RuO$_2$의 핵생성과 연속막 성장에 미치는 효과에 대해 조사하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.636-639
• /
• 2001

InGaN/GaN multiple quantum wells (MQWs) grown with various growth interruptions between the InGaN well and GaN barrier by metal-organic chemical vapor deposition were investigated using photoluminescence, high-resolution transmission electron microscopy, and energy filtered transmission electron microscopy (EFTEM). The luminescence intensity of the MQWs with growth interruptions is abruptly reduced compared to that of the MQW without growth interruption. Also, as the interruption time increases the peak emission shows a continuous blue shift. Evidence of indium clustering is directly observed both by using an indium ratio map of the MQWs and from indium composition measurements along an InGaN well using EFTEM. The higher intensity and lower energy emission of light from the MQW grown without interruption showing indium clustering is believed to be caused by the recombination of excitons localized in indium clustering regions and the increased indium composition in these recombination centers.

• Electrical & Electronic Materials
• /
• v.11 no.10
• /
• pp.94-99
• /
• 1998

Suitable replacement materials for ultrathin SiO2 in deeply scaled MOSFETs such as lattice polarizable films, which have much higherpermittivities than SiO2, have bandgaps of only 3.0 to 4.0 eV. Due to these small bandgaps, the reliability of these films as a gate insulator is a serious concern. Ramped voltage, time dependent dielectric breakdown, and hot carrier effect measurements were done on 190 layers of TiO2 which were deposited through the metal-organic chemical vapor deposition of titanium tetrakis-isopropoxide (TTIP). Measurements of the high and low frequency capacitance indicate that virtually no interface state are created during constant current injection stress. The increase in leakage upon electrical stress suggests that uncharged, near-interface states may be created in the TiO2 film near the SiO2 interfacial layer that allow a tunneling current component at low bias.

• Journal of the Semiconductor & Display Technology
• /
• v.5 no.2 s.15
• /
• pp.1-5
• /
• 2006

The GaN thin film on the 8 periods InGaN/GaN multi-quantum well structure was grown on the sapphire substrate using metal-organic chemical vapor deposition. The nano-scaled triangular-lattice holes with the diameter of 150 nm were patterned on a polymethylmethacrylate blocking film using an electron beam nano-lithography system. The thin slab and two-dimensional photonic crystals with the thickness of 28 nm were fabricated on the GaN layer for the blue light diffraction sources. The photonic crystal with the lattice parameter of 460 nm enhances spectral intensity of photoluminescence indicating that the photonic crystals provides the source of nano-diffraction for the blue light of the 450-nm wavelength.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1996.06a
• /
• pp.36-37
• /
• 1996

• Journal of the Korean Ceramic Society
• /
• v.31 no.10
• /
• pp.1123-1132
• /
• 1994

Bi-Sr-Ca-Cu-O superconductor thin films were prepared on MgO and LaAlO3 substrates by MOCVD technique. The films deposited on MgO and LaAlO3 substrates became superconducting at 64 K and 70 K respectively. The measured critical current density of thin film deposited on LaAlO3 substrate was around 104 A/$\textrm{cm}^2$. After annealing at $700^{\circ}C$ for 3 hours, the critical transition temperature(Tc) of films deposited on LaAlO3 was changed from 70 K to 74 K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.33-36
• /
• 2004

탄소 도핑$(5{\times}10^{19}\;cm^{-3})$된 p-type GaAsSb 에피층 위에, Ti/Pt/Au, Pd/Au, Pd/Ir/Au를 이용한 다층 오믹 접촉을 제작하였다. MOCVD(metal-organic chemical vapor deposition)를 이용하여 성장시킨 이 p-GaAsSb의 정공 이동도는 탄소의 도핑 농도가 매우 높음에도 불구하고, $50\;cm^2/Vs$로 측정되었다. 오믹 접촉의 전기적 특성을 측정하기 위하여 TLM(Transfer length method)를 이용하였다. Pd/Ir/Au을 이용한 오믹접촉의 specific contact resistivity는 $10^{-8}\;ohm-cm^2$ 보다 작은 수치를, transfer length는 100 nm보다 작은 수치를 보였으며, Ti/Pt/Au을 이용한 ohmic contact의 specific contact resistivity는 $10^{-7|\;ohm-cm^2$ 보다 작은 수치를, transfer length는 400 nm보다 작은 수치를 나타내었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.4
• /
• pp.343-346
• /
• 2010

We have investigated growth of CdTe thin films by using (As, GaAs) buffer layers for application of large scale IR focal plane arrays(IFPAs). Buffer layers were grown by molecular beam epitaxy(MBE), which reduced the lattice mismatch of CdTe/Si and prevented native oxide on Si substrates. CdTe thin films were grown by metal organic chemical deposition system(MOCVD). As a result, polycrystalline CdTe films were grown on Si(100) and arsenic coated-Si(100) substrate. In other case, single crystalline CdTe(400) thin film was grown on GaAs coated-Si(100) substrate. Moreover, we observed hillock structure and mirror like surface on the (400) orientated epitaxial CdTe thin film.