High rate growth highly crystallized microcrystalline silicon films using SiH 4/H 2 high-density microwave plasma

Abstract

The plasma parameter for fast deposition of highly crystallized microcrystalline silicon (μc-Si) films with low defect density is presented using the high-density and low-temperature microwave plasma (MWP) of a SiH 4–H 2 mixture. A very high deposition rate of ∼ 65 Å/s has been achieved at SiH 4 concentration of 67% diluted in H 2 with high Raman crystallinity I c / I α > 3 and low defect density of 1–2 × 10 16 cm − 3 by adjusting the plasma condition. Contrary to the conventional rf plasma, the defect density of the μc-Si films strongly depend on substrate temperature T s and it increased with increasing T s despite T s below 300 °C, suggesting that the real surface temperature at the growing surface was higher than the monitored value. The sufficient supply of deposition precursors such as SiH 3 at the growth surface under an appropriate ion bombardment was effective for the fast deposition of highly crystallized μc-Si films as well as the suppression of the incubation and transition layers at the initial growth stage.