Novel High-Density Microwave Plasma Utilizing an Internal Spoke Antenna for Fast Deposition of Microcrystalline Silicon Films

Novel high-density and low-temperature microwave plasma utilizing an internal spoke antenna is demonstrated. No quartz glass plate is required to maintain a high-density plasma using the alumina-ceramic-coated spoke antenna. Consequently, the plasma source is fairly simple. This microwave plasma maintains the uniform state over a diameter of 22 cm with a high electron density of 10¹¹ cm^-3 and a low temperature of 1–3 eV as well as a higher traveling efficiency of the microwave power to the chamber than that of the external one. A fast deposition rate of ∼ 40 Å/s is achieved for highly crystallized microcrystalline silicon (µc-Si:H) formation from SiH₄ and H₂ under lower-power-supply conditions. This high-density microwave plasma utilizing an internal spoke antenna has a high potential for larger-area thin film processing.