Preparation of microcrystalline silicon films at ultra high-rate of 10 nm/s using high-density plasma

Abstract

We have developed a novel technique for large-area high-rate-growth of microcrystalline silicon films by plasma-enhanced chemical vapor deposition, designing a novel cathode with interconnected multi-holes, which generates uniformly flat-distributed stable high-density plasma spots near the cathode-surface. A high growth rate of 9.3 nm/s has been achieved showing an efficient gas dissociation. Improvement of the quality of high-rate-grown films was discussed with regard to the temperature of the film-growing-surface that is affected by the plasma under high-rate-growth conditions. By reducing power and increasing total gas flow rate with adjusted hydrogen dilution of silane, we succeeded in the reduction of defect density for high-rate-grown films. As a result, microcrystalline silicon films with low defect density of 4–6 × 10 15 cm −3 were obtained at a high growth rate approaching 8 nm/s, demonstrating the effectiveness of the novel cathode design.