The schematic diagram of the experiment setup used for the generation and characterization of ICP is shown in the Figure 3. The nitrogen discharge plasma is generated by 13.56MHz RF [9{11] generator
having 50 resistance, connected across a spiral planar coil shaped electrode of copper having 13 turns and 30 cm diameter placed at the top opening of a grounded cylindrical plasma chamber of stainless steel. The plasma chamber is 31 cm in diameter and 24 cm in height with four main vacuum tight multi role ports of 9.8 cm diameter each.The spiral planar coil is insulated from the chamber by a 1.2 cm thick quartz plate which not only serves as an insulator between the coil and plasma chamber but also helps in maintaining the vacuum inside the chamber. In order to keep the re°ected power below 2% and to maximize the power transfer from the RF generator to discharge gas,an automatic impedance matching network consisting of a tuning unit and a control unit is connected between 13.56MHz RF generator and spiral planar coil [12, 13]. For the °ow mode operation and generation of low pressure discharge plasma, a rotary vane pump is connected across the chamber which has the capability of lowering the pressure up to 10¡3 mbar. The pressure inside the chamber is monitored by a pirani gauge and the gas °ow rate from the main cylinder to the plasma
chamber is controlled by the mass °ow meter. In this experiment the °ow rate of nitrogen gas is kept constant at 50 sccm.