Impact of the Ge Content on the Bandgap-Narrowing Induced Leakage Current of Recessed $hbox{Si}_{1 - x}hbox{Ge}_{x}$ Source/Drain Junctions |
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Authors: | Gonzalez M.B. Simoen E. Vissouvanadin B. Verheyen P. Loo R. Claeys C. |
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Affiliation: | Interuniversity Microelectron. Center, Leuven; |
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Abstract: | The purpose of this paper is to evaluate the impact of process-induced stress on the generation current of fully strained Si1- xGex source/drain junctions. The Ge content of the compressively strained SiGe epitaxial layer plays a key role in the tensile stress levels present in the underlying Si substrate. Current-voltage (I-V) measurements were employed to further investigate the leakage current enhancement due to the stress-induced bandgap narrowing in the Si depletion region, when no extended defects are formed. An empirical approach is proposed to describe the Ge content dependence of the bandgap-shrinkage-induced leakage current. An increase of the intrinsic carrier concentration as a function of the stress mismatch is observed. Moreover, the role of the epilayer thickness in the generation current is also discussed. |
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