Investigation of plasma parameters in 915 MHz ECR plasma with SiH₄/H₂ mixtures

The plasma parameters in 915 MHz ECR plasma with SiH₄/H₂ mixtures were investigated using a heated Langmuir probe where extremely high dilution ratio of H₂ to SiH₄ was used for preparing microcrystalline silicon thin films. As the incident microwave power was increased, the electron temperature (T_e) decreased from 7 eV to 2-3 eV and the electron density (n_e) increased from 0.5 x 10¹¹ cm^-3 to 1.3 x 10¹¹ cm^-3, that is, low T_e ECR plasma with high n_e was realized using 915 MHz microwaves. As a result of the film deposition, it was found that there is a correlation between the T_e and crystallinity of the microcrystalline silicon. Furthermore, it was shown that high deposition rate can be realized by increasing the gas flow rate