New material and selective growth of thin SiC films for environmental and optoelectronics devices

Abstract

A thin films of crystalline Silicon Carbide (c-SiC) and amorphous Silicon Carbide (a-Si1-xCx) were grown onto p-type Si substrate by using a hot target p-type polycrystalline 6H-SiC target by both methods: Pulsed Laser Deposition (PLD) with KrF excimer laser and sputtering DC magnetron with a mixture of gas Ar:H2, respectively. The target ldquo6H-SiCrdquo used to elaborate the thin films, is realized from a mixture of 1SiO2 with 3C (carbon) ldquo1SiO2 + 3Crdquo heated in an oven at 2500 degC. In this experiment, we mainly investigated the dependence of structural and optical properties of c-SiC and a-Si1-xCx. From the comparative study, different techniques are used, Scanning Electronic Microscopy, Secondary Ion Mass Spectrometry, Fourier Transform Infrared spectroscopy and photoluminescence. A SEM analysis indicates a quasi-high quality of the crystalline films c-SiC compared to the one grown by sputtering methods that reveals defects on the surface of SiC films. In addition, a SIMS analysis gives a ratio constant ratio Si/C = 1.07 for c-SiC films obtained by PLD method, in contrary the one obtained by sputtering gives a variable ratio versus depth, this last property of the amorphous a-Si1-xCx can be used to elaborate a Schottky photodiode with a high quantum efficiency. Finally, a crystalline 0.9 mum of thin SiC layer was elaborated using PLD method at low temperature deposition and 0.23 mum of amorphous a-Si1-xCx layer was realized by sputtering DC magnetron. In addition, the structural and optical properties of the two films are also strongly different, these property allow to used the films in much applications on optoelectronics devices such as UV photodiode and environmental as gas sensors.