Generation of high-density plasma via transparent electrode in capacitively coupled plasma

Abstract

The effect of transparent capacitively coupled plasmas (TCCP) is investigated by using a transparent ITO electrode instead of the metal electrode of capacitively coupled plasmas (CCP). To compare CCP and TCCP, the CCP is made by coating the powered electrode with metal and the TCCP is made by coating the powered electrode with Indium Tin Oxide (ITO) on the quartz window. To compare the properties of electrodes based on ITO electrodes and metal electrodes in the same size reactor, electrode voltage, electron temperature and electron density were measured at various applied RF powers and pressures at 13.56 MHz. The electron temperature decreases overall with increasing pressure, regardless of the electrode type. We observed that the total voltage between the powered electrode and ground is about two times higher for the TCCP than for the CCP. In addition, the electron density of the TCCP increases significantly by about two times that of the CCP. In this TCCP, the voltage applied to the sheath is calculated based on the expectation that the increase in electron density is related to the voltage applied to the sheath. The results of calculating the voltage applied to each sheath of the CCP and the TCCP agree well with our expectations. In addition, we calculated the total power absorption per unit area and confirmed that the total power absorption per unit area is significantly higher in the TCCP than in the CCP.