Secondary electron energy profiles as a diagnotic tool for RF plasma sheaths

Summary form only given, as follows. Ion-induced secondary electron energy profiles from a radio frequency biased (13.56 MHz) electrically insulating (Al/sub 2/O/sub 3/) electrode placed adjacent to an inductively coupled plasma (ICP) discharge are studied both experimentally and theoretically. Plasma feedstock gases include Ar, He, H/sub 2/, and N/sub 2/ over the pressure range of 2-20 m Torr. Radio frequency electrode bias voltages of 140, 285, and 425 V (peak to ground) are employed and the complete electron energy spectrum is measured 14 cm from the RF biased electrode using a differentially pumped retarding potential analyzer. The experimental measurements are compared to a collisionless Child-Langmuir RF sheath model, indicating that this technique is a useful in-situ diagnostic method to check the validity of RF sheath theories.