Probing Band-Tail States in Silicon MOS Heterostructures with Electron Spin Resonance

Authors:
  • RJR. M. Jock
    R. M. Jock
  • KCK. D. Childs
    K. D. Childs
  • LTL. A. Tracy
    L. A. Tracy
  • MLM. P. Lilly
    M. P. Lilly
  • MCM. S. Carroll
    M. S. Carroll
  • SLS. A. Lyon
    S. A. Lyon
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Abstract
We present an electron spin resonance (ESR) approach to characterize shallow electron trapping in band-tail states at Si/SiO2 interfaces in metal-oxide-semiconductor (MOS) devices and demonstrate it on two MOS devices fabricated at different laboratories. Despite displaying similar low temperature (4.2 K) peak mobilities, our ESR data reveal a significant difference in the Si/SiO2 interface quality of these two devices, specifically an order of magnitude difference in the number of shallow trapped charges at the Si/SiO2 interfaces. Thus, our ESR method allows a quantitative evaluation of the Si/SiO2 interface quality at low electron densities, where conventional mobility measurements are not possible.