| AVS 59th Annual International Symposium and Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM-ThP |
| Session: | Electronic Materials and Processing Poster Session |
| Presenter: | H. Zheng, University of Wisconsin-Madison |
| Authors: | H. Zheng, University of Wisconsin-Madison M.T. Nichols, University of Wisconsin-Madison D. Pei, University of Wisconsin-Madison G.A. Antonelli, Novellus Systems, Inc. Y. Nishi, Stanford University J.L. Shohet, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
The change in the electrical surface conductivity of SiO2 and SiCOH during exposure to vacuum ultraviolet radiation is investigated1. To measure the change in conductivity, special fabricated patterned titanium finger “comb structures” are deposited on dielectric films and exposed to synchrotron radiation in the range of 50–300 nm, which is in the energy range of most plasma vacuum-ultraviolet radiation. For the measurements of the VUV-induced currents along the surface of the layer in between the titanium fingers, electrical connections are made from the test structure to outside circuitry through vacuum feedthroughs. A numerical simulation shows that the bulk current is too small to account for the measured values and most of the current indeed flows across the surface of the dielectric film in the test structure. By measuring the I-V curve of the comb test structures under controlled fluxes of VUV light, we determine that the measured current per unit photon-flux density is linear with applied electric field up to a saturation value that is VUV flux limited. This permits the surface conductivity to be calculated based on a simple photoconductor model. The increase in surface conductivity induced by VUV radiation can be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge.
This work is supported by the National Science Foundation under Grant CBET-1066231 and the Semiconductor Research Corporation under contract 2008-KY-1781. We also thank M. Severson for helping set up the VUV exposure.
1 C.Cismaru, J.L. Shohet and J.P. McVittie, Applied Physics Letters, 71 2191 (2000).