Newly developed high-speed rotating disk chemical vapor deposition equipment for poly-Si films

We have developed high-speed rotating disk chemical vapor deposition (CVD) equipment. A high deposition rate, good thickness uniformity and few particles were achieved for polycrystalline silicon (poly-Si) film deposition on a 200-mm-diameter silicon (Si) wafer, by optimizing the structure of the rotating disk CVD equipment. A magnetic bearing motor was used for rotating and controlling the 200-mm-diameter wafer at 3000 rpm, and the substrate temperature was controlled to be 600-900°C. Gas flow was also controlled to avoid the re-adsorption of reaction by-products onto the wafer surface. A deposition rate of 316 nm/min, a film thickness nonuniformity ±3%, and less than 20 particles (over 200 nm in diameter) were achieved at a deposition temperature of 680°C for poly-Si deposition on the 200-mm-diameter wafer. These results show that the number of particles can be reduced even at a high deposition rate. The mechanisms of the high performance for poly-Si deposition are considered to be the reduction in the thickness of the boundary layer of temperature above the wafer surface and the suppression of the vapor-phase reaction.