Hwang, Gyeong S. and Giapis, Konstantinos P. (1997) Ion mass effect in plasma-induced charging. Applied Physics Letters, 71 (14). pp. 1942-1944. ISSN 0003-6951 http://resolver.caltech.edu/CaltechAUTHORS:HWAapl97c
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Simulations of charging and profile evolution during etching of high aspect ratio polysilicon gates in typical high-density plasmas containing heavy ions (e.g., BCl<sub>3</sub><sup> + </sup>, Cl<sub>2</sub><sup> + </sup>), predict a reduction in charging and notching when lighter ions (e.g., He + ) are added. The reduction occurs because of the influence of the ion mass on the ratio R of the ion sheath transit time to the rf period, which determines the spread in the ion energy distribution at the wafer. The effect is most pronounced when R <= 0.1–0.2 for light ions and, simultaneously, R >= 0.6 for heavy ions; then, more light ions arrive at the patterned structure with low energies, where they help decrease localized charging. When the rf bias frequency is reduced so that R <= 0.3 for all ions, the effect disappears.
|Additional Information:||©1997 American Institute of Physics. (Received 20 June 1997; accepted 30 July 1997) This work was supported by a National Science Foundation-Career Award and a Camille Dreyfus Teacher-Scholar Award to KPG. An Applied Materials Scholarship in partial support of GSH is gratefully acknowledged.|
|Subject Keywords:||silicon; elemental semiconductors; sputter etching; surface charging|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||07 Sep 2006|
|Last Modified:||26 Dec 2012 09:01|
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