Capacitively coupled microplasma source on a chip at atmospheric pressure

A small-scale and low-power 13.56 MHz capacitively coupled plasma is generated in a capillary, whose cross section is 65-500 x 500-5000 mum, on a quartz chip of 20 x 20 mm at atmospheric pressure. The capillary is sandwiched between parallel-plate electrodes which are externally located on a chip. A pi -type matching network is miniaturized and appropriately designed to satisfy the resonance condition with the excitation frequency, so that helium plasma ignites at an incident power of 1-3 W. The atomic excitation temperature measured from the intensity distribution of He I lines is about 1900 K at atmospheric pressure. This result suggests that a low-electronic-temperature plasma is obtained.