Probing Band-Tail States in Silicon MOS Heterostructures with Electron   Spin Resonance
  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. 
R. M. Jock, S. Shankar, A. M. Tyryshkin, Jianhua He, K. Eng, K.D.   Childs, L. A. Tracy, M. P. Lilly, M. S. Carroll, S. A. Lyon
cond-mat.mtrl-sci cond-mat.mes-hall