• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.387-390
• /
• 2002

This paper presents deposition and characterizations of microcrystalline silicon(${\mu}$c-Si:H) films prepared by hot wire chemical vapor deposition at substrate temperature below 300$^{\circ}C$. The SiH$_4$ concentration[F(SiH$_4$)/F(SiH$_4$).+(H$_2$)] is critical parameter for the formation of Si films with microcrystalline phase. At 6% of silane concentration, deposited intrinsic ${\mu}$c-Si:H films shows sufficiently low dark conductivity and high photo sensitivity for solar cell applications. P-type ${\mu}$c-S:H films deposited by Hot-Wire CVD also shows good electrical properties by varying the rate of B$_2$H$\_$6/ to SiH$_4$ gas. The solar cells with structure of Al/nip ${\mu}$c-Si:H/TCO/g1ass was fabricated with single chamber Hot-Wire CVD. About 3% solar efficiency was obtained and applicability of HWCVD for thin film solar cells was proven in this research.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.161-162
• /
• 2006

Scaling rules for TFT application devices have led to the necessity of ultra thin dielectric films and high-k dielectric layers. In this paper, The advantages of high concentration of nitrogen in silicon oxide layer deposited by using $N_2O$ in Inductively Coupled Plasma Chemical Vapor Deposition (ICP-CVD) reported about Ellipsometric measurement, Capacitance-Voltage characterization and processing conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1991.10a
• /
• pp.63-67
• /
• 1991

Amorphous silicon films were deposited on glass, [100] single crystal silicon wafer with thermally grown silicon dioxide, and [100] silicon wafer substrates by Plasma Enhanced Chemical Vapor Deposition(with argon diluted silane source gas). Growth rate, UV optical band edge, and the hydrogen quantity in the amorphous silicon films have been investigated as a function of the preparation conditions by measuring film thickness, UV-absorbency, and FT-IR transmittance. The growth rate of the ${\alpha}$-Si:H films increases with increasing substrate temperture, flow rate and R.F. power density. The UV optical band edge shifts to blue with the increases in the deposition pressure. Increasing substrate temperature shifts the UV optical band edge of the films to red. Hydrogen quantity in the ${\alpha}$-Si:H films increases with an increases in the R.F. powr and decreases with an increase in the substrate temperature.

• Journal of the Korean Vacuum Society
• /
• v.3 no.1
• /
• pp.71-76
• /
• 1994

The electrical characteristics of the capacitor dielectric films of amorphous silicon-nit-ride-oxide(ANO) structures are compared with the capacitor dielectric films of oxide-nitride-oxide (ONO) structrues The electrical characteristics of ONO and ANO films were evaluated by high frequency(1 MHz) C-V high frequency C-V after constant voltage stree I-V TDDB and refresh time measurements. ANO films shows good electrical characteristics such as higher total charge to breakdown storage capacitance and longer refresh time than ONO films. Also it makes little difference that leakage current and flat band voltage shyift(ΔVfb)of ANO ana ONO films.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.141-141
• /
• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.172-175
• /
• 2009

n-type crystalline silicon wafers were passivated with intrinsic a-Si:H thin films on both sides using HWCVD. Minority carrier lifetime measurement was used to verify interface passivation properties between a-Si:H thin film and crystalline Si wafer. Thin film interface characteristics were investigated depending on $H_2/SiH_4$ ratio and hot wire deposition temperature. Vacuum annealing were processed after deposition a-Si:H thin films on both sides to investigate thermal effects from post process steps. We noticed the effect of interface passivation properties according to $H_2/SiH_4$ ratio and hot wire deposition temperature, and we had maximum point of minority carrier lifetime at H2/SiH4 10 ratio and $1600^{\circ}C$ wire temperature.

• Journal of the Korean Vacuum Society
• /
• v.12 no.4
• /
• pp.263-268
• /
• 2003

Precise thickness control and excellent properties of silicon nitride thin films are essential for the next-generation semiconductor and display devices. In this study, silicon nitride thin films were deposited by batch-type atomic layer deposition (ALD) method using $SiC1_4$ and $NH_3$ as the precursors at temperatures ranging from 500 to $600^{\circ}C$. Thin film deposition using a batch-type ALD reactor was a layer-by-layer atomic growth by self-limiting surface reactions, and the thickness of the deposited film can be controlled by the number of deposition cycles. The silicon nitride thin films deposited by ALD method exhibited composition, refractive index and wet etch rate similar with those of the thin films deposited by low-pressure chemical vapor deposition method at $760^{\circ}C$. The addition of pyridine mixed with precursors increased deposition rate by 50%, however, the films deposited with pyridine was readily oxidized owing to its unstable structure, which is unsuitable for the application to semiconductor or display devices.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.63-63
• /
• 1999

The stability of hydrogenated amorphous silicon (a-Si:H) films under the light soaking are very important since the applications of a-Si:H films are solar cells, color sensors, photosensors, and thin film transistors(TFTs). We found the changes of the electric conductivity and the conductivity activation energy (Ea) of a-Si:H films by argon radical annealing. The deposition rate of a-Si:H films depends on the argon radical annealing time. The optical band gap and the hydrogen contents in the a-Si:H films are changes along the argon radical annealing time. We will discuss the microscopic processes of argon radical annealing in a-si:H films.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.64.2-64.2
• /
• 2011

Recently, Silicon Germanium (SiGe) alloys have been received considerable attention for their great potentials in advanced electronic and optoelectronic devices. Especially, microcrystalline SiGe is a good channel material for thin film transistor due to its advantages such as narrow and variable band gap and process compatibility with Si based integrated circuits. In this work, microcrystalline silicon-germanium films (${\mu}c$-SiGe) were deposited by DC/RF magnetron co-sputtering method using Si and Ge target on Corning glass substrates. The film composition was controlled by changing DC and RF powers applied to each target. The substrate temperatures were changed from $100^{\circ}C$ to $450^{\circ}C$. The microstructure of the thin films was analyzed by x-ray diffraction (XRD) and Raman spectroscopy. The analysis results showed that the crystallinity of the films enhances with increasing Ge mole fraction. Also, crystallization temperature was reduced to $300^{\circ}C$ with $H_2$ dilution. Hall measurements indicated that the electrical properties were improved by Ge alloying.

• Journal of the Korean Ceramic Society
• /
• v.28 no.11
• /
• pp.859-864
• /
• 1991

High quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2$\times$2 $\textrm{cm}^2$ area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 50$0^{\circ}C$ in films with thickness above 360 nm. Metastable pyrochlore structures were observed in films with thickness of 160 nm when heat treated at 500 and $600^{\circ}C$, but these structure did not appear in films with thickness of 360 nm. The thickness dependence in crystal structure of films was studied. by varying the substrate condition and analyzing the interface between the film and substrate. In native oxide films on silicon stbstrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide.