DEEP AND SHALLOW ELECTRON TRAPPING IN THE BURIED OXIDE LAYER OF SIMOXSTRUCTURES

Electrons were injected by UV light into the buried oxide (BOX) layer of pseudo-separation by implantation of oxygen structures in which the original top Si layer was replaced by a metal electrode. From the pho tocurrent and metal oxide semiconductor C-V characteristics, the trapp ing cross sections, density, and location of the electron traps were d etermined. Two deep neutral traps with (3 +/- 1) x 10(-16) and (2 x 1) x 10(-17) cm2 trapping cross sections are responsible for fixed negat ive charge formation under electron injection. There are also shallow traps present which are responsible for transient effects with a time constant of about 100 s associated with photocurrents. The cross secti on of the shallow traps is of the order of 10(-11) cm2 indicating that the traps are some inclusions (clusters) rather than network defects in the oxide. Both the deep and shallow traps are in the vicinity of t he Si-substrate/BOX interface.