Investigation of Nano-thin β-SiC Layers for Chemical Sensors

Abstract

ABSTRACTSilicon Carbide possesses a combination of properties that make it ideal for use in electronics. Its high values of electric breakdown field, melting point and saturated electron drift velocity have attracted the attention of the semiconductor community. Although the interest in β-SiC/Si devices has intensified in recent years [1-2], little focus has been given to the study of nano-thin film devices. Monocrystalline nano-thin β-SiC films have been reproducibly grown on Si (100) by Gas Source Molecular Beam Epitaxy (GSMBE). Auger Electron Spectroscopy and Reflection High Energy Electron Diffraction characterization have confirmed a growth consistent of β-SiC/Si. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization has determined film thicknesses of 30nm. These nano-films have been used in the fabrication of Metal-Semiconductor-Metal (MSM) devices formed from aluminum Schottky contacts. Under electrical characterization, these MSM devices have exhibited unique properties in that the dominant conduction path does not occur at the β-SiC/Si interface [3] as previously reported, but within the entire β-SiC layer. It is proposed that the device is isolated from the Silicon substrate and due to the nano-thin β-SiC films used in this work the differentiation between surface and ‘bulk’ is not clear. Results obtained through chemical experimentation have indicated that conduction is largely dependent on the surface condition of the device. This suggests the possibility for nano-thin, surface-like, β-SiC films to be used in chemical agent sensors.