Improve silane utilization for silicon thin film deposition at high rate

In order to investigate the silane utilization during silicon thin film deposition, one quadrupole mass spectrometer was used to monitor the partial pressure of silane during high pressure and high power deposition process. Relationship of silane consumption with silane concentration, excitation power and reaction pressure was investigated. The results show that increasing silane concentration leads to lower silane consumption. Increasing excitation power can improve the silane utilization, which is proved by higher deposition rate. However, when the power is higher than a certain value, much more power will consume by the transmission line and matching network. The power coupled into the plasma saturates to a certain value and then no more silane decomposes any more. In addition, the silane consumption decreased and then increased with increasing reaction pressure, which is related with the voltage of electrodes. These results could help to improve silane utilization for low cost production and better quality of film.