| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 104 === This study investigates the effects of different ammonia/ethane (NH3/C2H6) ratios on the properties of p-type amorphous carbon thin films (a-C:H(N)) deposited on n-type silicon (n-Si) substrate prepared by plasma enhanced chemical vapor deposition. The radio-frequency power, substrate temperature, and working pressure were kept at 150 W, 298 K, and 60 Pa, respectively. Especially, the thickness of carbon thin film was fixed at 40 nm. This experiment also measured the active species of plasma, and the microstructure, optical and electrical properties of carbon thin films. The experimental results indicate that as the NH3/C2H6 ratio is 2, the N-H and C-N species in the plasma, and the N/C ratio and permittivity of carbon films have the maximum value. The sp2 carbon fraction and ID/IG of carbon films increase with increasing the NH3/C2H6 ratio, but the optical gap, resistivity, and built-in voltage decreases. This indicates that the structure of carcon film shifts to graphite-like. This study also analyzed the current-voltage and capacitance-voltage characterics of the a-C:H(N)/n-Si device. As the NH3/C2H6 ratio is 2, the a-C:H(N)/n-Si device has the best electrical property. In this case, the ideality factor, built-in voltage, series resistance, and shunt resistance are 1.26, 0.21 eV, 349 Ω, and 15.6 kΩ, respectively.
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