| Research Abstract |
Silicon carbide (SiC) is a wide-band-gap semiconductor with high thermal stability, excellent resistance to chemical attack, high thermal conductivity, high breakdown electron mobility, and high electric field. These properties favor this material for applications of electronic and optoelectronic devices. Polycrystalline SiC films can be fabricated as blue-emitting diodes and as high power devices. Therefore, SiC films have been fabricated on Si(lOO) substrates by using several methods, including chemical vapor deposition, sputtering, laser ablation, evaporation, molecular beam epitaxy and carbon-ion implantation.
In this study, we develop a new pulsed laser deposition (PLD) method with a cross-magnetic field, ion-beam source and a DC bias to synthesize crystalline SiC films. The laser beam was focused on the SiC targets. After 18000 laser pulses at a 10 Hz repetition rate, the deposition process was completed. All samples were analyzed by a field-emission scanning electron microscopy (
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FE-SEM), Auger electron spectroscopy (AES), atomic force microscope (AFM), glancing-angle X-ray Diffraction (GXRD), an energy-dispersive X-ray analyzer (EDX), Fourier transform infrared spectroscopy (FT-IR). An optical multichannel analyzer (OMA) with a 1024 photodiode array detected the optical emissions from the plasma plume generated by the pulsed Nd : YAG laser irradiation. The Si/C composition ratio is affected by the substrate bias voltage and methane gas pressure. FT-IR measurement indicates the presence of a Si-C bond stretching. FE-SEM observation shows that the surface of the film prepared using PLD is smooth and pinhole-free. The degree of crystallinity of the prepared films, characterized by GXRD, increases with increasing substrate temperature and decreasing methane gas pressure. Cross magnetic field can control the shape of the plasma plume. We prepared CrC, WC, SiC, TiC, CBN, SiN, TaN films as a hard material and SnOs, WOa films as a gas sensor material by PLD method. Our experiments show that our new PLD process is simple and effective technique to fabricate high-quality and large-area uniform ceramic thin films without droplets such as nitride, carbide and oxide films. It might be very important to study PLD process scientifically and industrially. Less
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