AVS 51st International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP17
Estimation of the Surface Potential Generated on Semiconductor Dielectric Materials Upon Exposure to Vacuum Ultraviolet Radiation Using a Monte-Carlo Simulation@footnote 1@

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: G.S. Upadhyaya, University of Wisconsin-Madison
Authors: G.S. Upadhyaya, University of Wisconsin-Madison
J.L. Shohet, University of Wisconsin-Madison
J.L. Lauer, University of Wisconsin-Madison
Correspondent: Click to Email
The effect of Vacuum Ultraviolet Radiation (VUV) on dielectric materials during plasma processing is significant. During processing, charge deposited on the material due to the plasma can adversely affect device reliability. Plasma-generated VUV radiation can beneficially deplete the charge by temporarily increasing the conductivity of the dielectric.@footnote 2@ This effect has been attributed to photoemission and photoconduction currents generated by VUV exposure.@footnote 3@ This can result in a positive surface charge, which is measured using a Kelvin Probe. However, the transport of electrons and holes generated by VUV radiation inside the dielectric is not well understood. To this end, we utilize a Monte-Carlo code, which includes the different processes that an electron undergoes once it has been released from an atom by a VUV photon. The code includes Rayleigh scattering of the incident VUV photons inside the dielectric, photoelectric absorption, and elastic and inelastic scattering of photoemitted electrons. The statistical data obtained from the simulation, such as the backscattering percentage for the electrons, the absorption coefficient of the electrons inside the dielectric, and the distances traveled by the electrons and holes is used to compute the surface potential generated on the dielectric. The simulation estimate is found to be in very good agreement with the experimental measurements made using the Kelvin Probe technique. The cross sections used for the various processes in the VUV regime are based on previous work where available. The remaining cross sections are estimated from experimental measurements in which synchrotron radiation is incident on the dielectric. @FootnoteText@ @footnote 1@ Supported by NSF under grant DMR-0306582. The UW Synchrotron is funded by NSF under grant DMR-0084402.@footnote 2@ C. Cismaru and J.L. Shohet, Appl. Phys. Lett. 76, 2191 (2000)@footnote 3@ J.L. Lauer, J.L. Shohet, et. al., J. Appl. Phys. 91, 1242 (2002).