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 (Te) decreased from 7 eV to 2–3 eV and the electron density (ne) increased from 0.5 × 1011 cm− 3 to 1.3 × 1011 cm− 3, that is, low Te ECR plasma with high ne was realized using 915 MHz microwaves. As a result of the film deposition, it was found that there is a correlation between the Te and crystallinity of the microcrystalline silicon. Furthermore, it was shown that high deposition rate can be realized by increasing the gas flow rate.