Double probe diagnostics based on harmonic current detection for electron temperature and electropositive ion flux measurement in RF plasmas

A double probe diagnostic using an ac bias signal between both probe tips was developed. The electron temperature and electropositive ion flux were derived by analyzing the first and third harmonic currents of the probe. The double probe was compared with the floating-type single probe at various RF powers and pressures in an inductively coupled plasma. The electron temperature and electropositive ion flux measured from the double probe agreed with the measurements from the floating-type single probe. This methodology can be applied to an electrically isolated diagnostic system for processing plasmas. (paper)