Thai Cheng Chua

Electron neutral collision frequency measurement with the hairpin resonator probe

Electron neutral collision frequency is measured using both grounded and floating hairpin resonator probes in a 27 MHz parallel plate capacitively coupled plasma. Operating conditions are 0.1–2 Torr (13.3–267 Pa) in Ar, He, and Ar–He gas mixtures. The method treats the hairpin probe as a two wire transmission line immersed in a dielectric medium. Measurements are obtained using a pressure and sheath correction process by sweeping over assumed collision frequencies in order to obtain the measured collision frequency. Results are compared to hybrid plasma equipment module simulations and show good agreement.

Nanoscale materials modification via low-energy reactive plasmas

Materials modification of thin films and nanoparticles through the use of reactive plasmas is discussed. Pulsed radio-frequency nitrogen plasmas have been well characterized through measurement of the ion energy distribution in the plasma. The low-energy nitrogen plasmas are successfully used for nitrogen incorporation into ultrathin MOSFET gate dielectrics, where nitrogen dose control and nitrogen profile control are both critical. The use of low-energy, pulsed radio-frequency reactive plasmas for other applications where composition and morphology need to be controlled at the nanometer scale is considered.