Stable Molecules in N2-H2 Plasmas Measured Using a Quartz Sensor

Stable molecules of N-2, H-2, and NH3 in N-2-H-2 plasmas were investigated using a quartz sensor (Q-sensor). Changes in the pressure-and temperature-normalized Q-sensor output (NQO) induced by plasma with radio-frequency (rf) input power were measured near plasma electrodes and shown to correlate to the relative ion signal intensity from NH3. The results confirm that gas composition changes in N-2-H-2 plasmas can be successfully measured from the NQO changes using the Q-sensor. The spatial distribution of NQO indicates that NH3 molecules are produced near plasma electrodes rather than by secondary gas reactions in the plasma, which also means that Q-sensor measurements can provide information regarding stable gas molecules in plasma. (C) 2013 The Japan Society of Applied Physics