• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.123-123
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• 1999

Amorphous hydrogenated silicon carbide (a-SiC:H) films were deposited at the temperature of 40$0^{\circ}C$ using plasma enhanced chemical vapor deposition. The a-SiC:H films were characterized by x-ray photoelectron spectroscopy (XPS) and nanoindentation method. By increasing the plasma power from 20W to 160W, the oxygen content of the a-SiC:H films were observed to decrease from 12.1% to 4.4%. On the other hand, the plasma power did not affect the ratio of carbon to silicon in our experiment where the 1, 3-disilabutane was used as the precursor. Microhardness of the films was observed to increase as the plasma power increased, while the elastic modulus was observed to gave a maximum value at the plasma power of 80W. Microhardness of the film is thought to be strongly affected by the content of adventitious oxygen in the film and it is concluded that the hardness of the film can be improved by increasing the plasma power.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.513-516
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• 1987

Hydrogenated amorphous silicon (a-Si:H) films have been deposited, for thye first time, by a remote plasma chemical vapor deposition. The hydrogen radical play a important role to control the deposition rate, The bonded hydrogen content to silicon is independent of hydrogen partial pressure in the plasma. Optical gap of deposited a-Si:H lies between 1.7eV and 1.8eV and all samples have sharp absorption edge. B-doped a-Si:H films by a RPECVD has a high doping efficiency compared with plasma CVD. The Fermi level of 100ppm B-doped film lies at 0.5eV above valence band edge.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1277-1279
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• 1993

As a highly information-oriented society developes, various kinds of amorphous semiconductor devices, such as solar cells, electrographic printers, image sensors, and flat-panel televisions, have been developed as man/machine interfaces. This paper proposed the laser CVD techniques to deposit hydrogenated amorphous silicon thin film on glass or dielectric substrate at low temperatures. Varying the deposition conditions, we examined optical and electrical charateristics of a-Si:H film deposited by Laser CVD.

• Solar Energy
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• v.7 no.1
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• pp.35-41
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• 1987

This paper presents a comprehensive computer simulation of hydrogenated amorphous p-i-n silicon solar cells. The physical mechanism governing solar cell operation has been modeled and solved numerically by Runge-Kutta-Gill method. Effects of gap state density, dopant impurity, diffusion length and interface recombination velocity on solar cell performance are investigated. Numerical results show that the electric field in i-region is not uniform but depends strongly on voltage and position. A rather poor fill factor may be due to the electric field variation and short diffusion length. It is found out that the life time should be improved in order to increase a fill factor and a conversion efficiency.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.4
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• pp.506-514
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• 1986

Experimental results are reported concerning temperture effects from room temperature to 100\ulcorner on the optical properties of N-and P-type hydrogenated amorphous silicon films prepared by RF glow discharege. Optical absorption coefficient and optical bandgap have been measured and analyzed as a function of temperature. Optical absorption coefficient increase monotonically with temperature, while the optical bandgape of doped amorphous silicons decrease linearly by about 4-7x10**-4 [ev/k].

• Korean Journal of Materials Research
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• v.26 no.1
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• pp.47-53
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• 2016

Silicon nitride ($SiN_x:H$) films made by plasma enhanced chemical vapor deposition (PECVD) are generally used as antireflection layers and passivation layers on solar cells. In this study, we investigated the properties of silicon nitride ($SiN_x:H$) films made by PECVD. The passivation properties of $SiN_x:H$ are focused on by making the antireflection properties identical. To make equivalent optical properties of silicon nitride films, the refractive index and thickness of the films are fixed at 2.0 and 90 nm, respectively. This limit makes it easier to evaluate silicon nitride film as a passivation layer in realistic application situations. Next, the effects of the mixture ratio of the process gases with silane ($SiH_4$) and ammonia ($NH_3$) on the passivation qualities of silicon nitride film are evaluated. The absorption coefficient of each film was evaluated by spectrometric ellipsometry, the minority carrier lifetimes were evaluated by quasi-steady-state photo-conductance (QSSPC) measurement. The optical properties were obtained using a UV-visible spectrophotometer. The interface properties were determined 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). In hydrogen passivation, gas ratios of 1:1 and 1:3 show the best surface passivation property among the samples.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.104-111
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• 2001

B-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films were prepared by plasma-enhanced chemical-vapor deposition in a gas mixture of $SiH_4, CH_4,\;and\; B_2H_6$. Physical and chemical properties of a-SiC:H films grown with varing the ratio of $B_2H_6/(SiH_4+CH_4)$ were characterized with various analysis methods including scanning electron microscopy (SEM), X-ray diffractometry (XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, secondary ion mass spectroscopy (SIMS), UV absorption CH_4spectroscopy and electrical conductivity measurements. With the B-doping concentration, the doping efficiency and the micro-crystallinity were decreased and the film became amorphous when $B_2H_6/(SiH_4{plus}CH_4)$ was over $5{\times}10^{-3}$. The addition of $B_2H_6$ gas during deposition decreased the H content in the film by lowering the quantity of Si-C-H bonds. Consequently, the optical band gap and the activation energy of a-SiC:H films were decreased with increasing the B-doping level.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.51-54
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• 1999

Hydrogenated amorphous silicon (a-Si:H) films are fabricated by Argon radical annealing (ArRA). The deposition rate of continuously deposited a-Si:H film is 1.9 $\AA$/s. As ArRA time are increased to 0.5 and 1 minute, the deposition rate are increased to 2.8 $\AA$/s and 3.3 $\\AA$/s. The deposition rate of a-si:H films with 2 and 3 minutes ArRA time are 3.3 $\AA$/s. As the ArRA time is increased, the optical band gap and the hydrogen contents in the a-Si:H films are increased and slightly decreased. The light-induced degradation of ArRA treated a-Si:H films are less than that of continuously deposited a-Si:H film. The dark conductivity and the conductivity activation energy ($E_a$) of continuously deposited a-Si:H film are decreased to 1/25 in room temperature and increased to 0.09eV By 1 hour light soaking, respectively. The dark conductivity and $E_a$ of ArRA treated a-Si:H film decreased to 1/3 in room temperature and increased to 0.03eV by 1 hour light soaking, respectively. We could improve the stability of a-Si:H films under the light soaking by ArRA technique and discussed the microscopic process of ArRA technique.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1295-1296
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• 2006

수소화된 비정질 실리콘 박막 트랜지스터(a-Si:H TFT)의 이력 현상이 능동형 유기 발광 다이오드(Active-Matrix Organic Light Emitting Diode) 디스플레이 패널을 구동할 경우에, 발생할 수 있는 잔상(Residual Image) 문제를 단위 소자 및 회로에서 실험을 통하여 규명하였다. 게이트 시작 전압을 바꾸어 VGS-ID 특성을 측정할 경우, 게이트 시작 전압이 5V에서 시작한 VGS-ID 곡선이 10V에서 시작한 VGS-ID 곡선에 비해 왼쪽으로 0.15V 이동하였다. 이러한 결과는 게이트 시작 전압의 차이에 의해 발생한 트랩된 전하량(Trapped Charge) 변화로 설명할 수 있다. 또한, 인가하는 게이트 전압 간격을 0.5V에서 0.05V로 감소시켰을 때 전하 디트래핑 비율의 변화(Charge De-trapping Rate)로 인하여, 이력 현상(Hysteresis Phenomenon)으로 인한 단위 소자에서의 문턱전압의 변화가 0.78V에서 0.39V로 감소함을 관찰하였다. 제작된 2-TFT 1-Capacitor의 ANGLED 화소에서 (n-1)번째 프레임에서의 OLED 전류가 (n)번째 프레임에서의 OLED 전류에 35%의 전류오차를 발생시키는 것을 측정 및 분석하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.618-623
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• 2006

Hydrogenated Diamond-like carbon (DLC) films were prepared by the radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method on silicon substrates using methane $(CH_4)$ and hydrogen $(H_2)$ gas. The wear track on the DLC films was examined after the ball-on disk (BOD) measurement with a Raman mapping method. The BOD measurement of the DLC films was performed for 1 to 3 hours with a 1-hour step time. The sliding traces on the hydrogenated DLC film after the BOD measurement were also observed using an optical microscope. The surface roughness and cross-sectional images of the wear track were obtained using an atomic force microscope (AFM). The novel Raman mapping method effectively shows the graphitization of DLC films of $300{\mu}m\times300{\mu}m$ area according to the sliding time by G-peak positions (intensities) and $I_D/I_G$ ratios.