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Proceedings Paper

Si1-x-yGexCy channel heterojunction PMOSFETs
Author(s): Soji John; Samit K. Ray; Sandeep K. Oswal; Sanjay K. Banerjee
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Paper Abstract

Strain-compensated Si1-x-yGexCy alloy appears attractive because it may eliminate the constraints in Si1- xGex device design involving high Ge concentrations, thicker active layers, and may allow relatively higher process temperature windows. PMOSFET devices were fabricated with partially strained Si1-x-yGexCy films with Ge-to-C ratio of 30:1 in order to preserve the valence band offset to confine holes. Bulk and epitaxial Si, Si1-xGex and completley strain-compensated Si1-x-yGexCy were also processed for comparison. An n+-poly gate PMOS process was used. The dc characteristics of the Si1-x- yGexCy PMOSFETs with channel lengths varying from 0.8 to 10 micrometer were evaluated between room temperature and 77 degrees Kelvin and were compared to those of Si and Si1-xGex PMOSFETs. The low field effective mobility in Si1-x-yGexCy devices were found to be higher than that of Si1-xGex and Si devices at low gate bias and room temperature as a result of partial strain compensation. However, with increasing transverse fields and with decreasing temperatures, Si1-x-yGexCy, we observed degradation in device performance. This enhancement at low gate bias was attributed to the strain stabilization effect of C. At higher C concentrations, degraded performance was observed. This first application of Si1-x-yGexCy in PMOSFETs demonstrates potential benefits in the use of C with the column IV heterostructure system.

Paper Details

Date Published: 27 August 1997
PDF: 6 pages
Proc. SPIE 3212, Microelectronic Device Technology, (27 August 1997); doi: 10.1117/12.284611
Show Author Affiliations
Soji John, Univ. of Texas at Austin (United States)
Samit K. Ray, Indian Institute of Technology (India)
Sandeep K. Oswal, Univ. of Texas at Austin (United States)
Sanjay K. Banerjee, Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 3212:
Microelectronic Device Technology
Mark Rodder; Toshiaki Tsuchiya; David Burnett; Dirk Wristers, Editor(s)

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