Detection of two dangling bond centers with trigonal symmetry at and below a (100) Si/SiO2 interface

Using electrical detection of electron paramagnetic resonance (EDEPR), two defect centers located at the Si (100)/SiO2 interface and in regions several mum below the silicon surface have been observed at a low temperature. Improvements in the EDEPR measurement technique enabled the experimental detection of the g-factor anisotropy of two centers, labeled P-ba and P-bb. Both appear with a [111]-oriented, trigonally symmetric g-tensor with g(parallel to)=2.0008/g(perpendicular to)=2.0098 and g(parallel to)=1.9974/g(perpendicular to)=2.0160, respectively (Deltag=+/-0.0004). The data of the P-ba center are very similar to those of the well known P-b0 center occurring on (100) oriented silicon. The location of the center which is significantly below the (100)Si/SiO2 interface is discussed. (C) 2001 American Institute of Physics.