Comparative study of low-temperature PECVD Of amorphous silicon using mono-, di-, trisilane and cyclohexasilane

The hydrogenated amorphous silicon a-Si:H films were grown by plasma-enhanced chemical vapor deposition (PECVD) using liquid cyclohexasilane Si
₆
H
₁₂
(CHS). The growth rate of a-Si:H was studied as a function of substrate temperatures in the range of 30 °C₄
. The same parameters were used for a- Si:H films grown using disilane (Si
₂
H
₆
) and trisilane (Si
₃
H
₈
) precursors. It was found that the a-Si:H film growth rate of CHS is lower with respect to those of mono-, di- and trisilane in an Ar plasma. Addition of ~10% of H
₂
dramatically increases the deposition rate for CHS-based films about 700% to 8 ¿/sec. The as-deposited films were characterized by FTIR and Raman spectroscopy to probe the hydrogen content and local bonding environment. It was found that the films grown using Ar/H
₂
mixtures as carrier gas have a reduced hydrogen content relative to polysilane fragments indicating higher quality amorphous silicon.