Diagnosis of hydrogen plasmas at low temperature and low pressure by spectroscopy and Langmuir probe
The emission spectroscopy and I-V characteristics of hydrogen plasmas excited in helicon-wave plasma chemical vapor deposition(HWP-CVD) device have been measured by emission spectroscopy method and Langmuir probe.The density of the excited hydrogen atoms,plasma density and electron energy distribution function(EEDF) were analyzed by corona model and Druyvestey method.The results indicate that the density of the excited hydrogen atoms increases with the increase of input power while decreases with the increase of pressure.The plasma density increase linearly with the increase of input power and reaches 1012 cm-3.The plasma density increases to a peak value and then decreases with the increase of pressure.The electron average energy increases gradually then gets saturated with the increase of input power and decreases with the increase of pressure.The results obtained from two methods were accordant.In the diagnosis of plasmas at low temperature and low pressure,combining the two methods can get more accurate information of plasma.