Visible photoluminescence from a-Si based alloy (a-SiN/sub x/) thin films deposited by plasma enhanced CVD

Summary form only given, as follows. Summary form only given. We have studied optical and structural properties of a-SiN/sub x/ thin films prepared by plasma method. While there are several methods of preparing a-Si based alloy (a-SiN/sub x/), plasma methods, such as PECVD and sputtering, have been widely used because of its good film quality and low deposition temperature. a-SiN samples were prepared on c-Si substrates by PECVD at 270/spl deg/C with pure NH/sub 3/ and 5%-diluted SiH/sub 4/ in N/sub 2/ as a precursor, and plasma was generated by RF power. All the deposition conditions were fixed except plasma power. We have observed two photolummescence (PL) peaks at about 3.0 eV and 2.5 eV at room temperature by He-Cd laser with 3.82 eV excitation energy. The former peak is due to the defect structures in SiN/sub x/ and the latter small silicon cluster. With the increase of plasma power, the PL properties of green band were improved with the increase of intensity, and the narrowing of full width at half-maximum. This result is attributed to the enhancement of nano-crystal silicon because the plasma power enhances the formation of radicals such as SiH, SiH/sub 2/, and SiH/sub 3/from precursors.