Electron spin resonance features of interface defects in thermal (100)Si/SiO2

Electron spin resonance (ESR) on thermal (100)Si/SiO2 predominantly exhibiting either the P-b0 or P-b1 interface defect confirms the P-b1 point symmetry as monoclinic-I with g(1) = 2.0058, g(2) = 2.00 735 +/- 0.00 010, and g(3) = 2.0022, where the g(2) direction is at 3 degrees +/- 1 degrees (towards the interface) with a [111] direction at 35.3 degrees with the interface plane. Its line width is found weakly dependent on magnet angle, exhibiting a strain induced spread sigma(g perpendicular to) similar to 0.00 035 in g(perpendicular to) about 2-3 times less than typical for P-b in (111) Si/SiO2. For P-b0, an axially symmetric g matrix is observed, with g(parallel to) = 2.0018 and g(perpendicular to) = 2.0081, and sigma(g perpendicular to) similar to 0.0009. From comparison of salient ESR data, it is concluded that P-b and P-b0 are chemically identical; however, systematic fabrication-induced variations in defect environment will lead to second order systematic shifts in average properties. The P-b1 defect is provisionally pictured as an unpaired Si bond on a defect Si atom at slightly subinterface plane position in the Si substrate, possibly facing an oxygen atom. (C) 1998 American Institute of Physics.