Stress-induced leakage current in p+ poly MOS capacitors with poly-Si and poly-Si0.7Ge0.3 gate material

V. E. Houtsma, J. Holleman, C. Salm, F. P. Widdershoven, P. H. Woerlee

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)


The gate bias polarity dependence of stress-induced leakage current (SILC) of PMOS capacitors with a p+ polycrystalline silicon (poly-Si) and polycrystalline Silicon-Germanium (poly-Si0.7Ge0.3) gate on 5.6-nm thick gate oxides has been investigated. It is shown that the SILC characteristics are highly asymmetric with gate bias polarity. This asymmetric behavior is explained by the occurrence of a different injection mechanism for negative bias, compared to positive bias where Fowler-Nordheim (FN) tunneling is the main conduction mechanism. For gate injection, a larger oxide field is required to obtain the same tunneling current, which leads to reduced SILC at low fields. Moreover, at negative gate bias, the higher valence band position of poly-SiGe compared to poly-Si reduces the barrier height for tunneling to traps and hence leads to increased SILC. At positive gate bias, reduced SILC is observed for poly-SiGe gates compared to poly-Si gates. This is most likely due to a lower concentration of Boron in the dielectric in the case of poly-SiGe compared to poly-Si. This makes Boron-doped poly-SiGe a very interesting gate material for nonvolatile memory devices.

Original languageEnglish
Pages (from-to)314-316
Number of pages3
JournalIEEE Electron Device Letters
Issue number7
Publication statusPublished - 1 Jul 1999
Externally publishedYes


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