EFFECT OF GROWTH TEMPERATURE ON THE CATALYST-FREE GROWTH OF LONG SILICON NANOWIRES USING RADIO FREQUENCY MAGNETRON SPUTTERING

We have grown metal catalyst free, straight Si nanowires (NWs) with high aspect ratio of about 130 on Si (100) substrate using radio frequency magnetron sputtering. Thin Si seed layer on thermally oxidized substrate was used for catalyst-free growth. Then Si deposition was done on that substrate using sputtering technique followed by heat treatment at different temperatures (900°C–1100°C). Sample heated at 1000°C results in straight, long, and uniform cylindrical shaped Si NWs with diameter 62–74 nm and length up to 8 μm, whereas sample heated above 1000°C transformed toward nanorods with larger diameter. However, no significant growth of Si NWs took place at 900°C. Sputter deposition technique provides an alternate fabrication route for Si NW synthesis. For comparison, we have also grown Au catalyst assisted Si NWs on Si (100) substrate by similar process. These nanowires also show similar morphology with diameter 48–65 nm and aspect ratio about 165. Growth mechanism and effect of growth temperatures on the structure and morphology of Si NWs are discussed.