Measurement of rotational temperature using SiH(A2Δ-X2Π) emission spectrum in SiH4-H2 plasmas

Based on the synthetic spectrum method of comparing with the experimental SiH(A2Δ-X2Π) diatomic molecular emission spectrum, the rotational temperatures of SiH4-H2 plasmas were investigated for various operating conditions. The plasma was generated between parallel plate electrodes biased at 40.68 MHz for thin film silicon deposition. Operating conditions of the gas pressure and the input power were varied from 2 to 8 Torr and from 200 to 600 W, respectively. Also, the total gas flow rate and H2/SiH4 gas flow ratio were changed. By increasing the input power, the rotational temperature was increased up to 865 K by more energetic electrons collisions. The magnitude of rotational temperature was reduced by 200 K due to particle cooling effects, with increasing the total flow rates and gas pressure. The experimental results were discussed further using Si/SiH emission intensity ratio to show the characteristics of electron temperature.