Capacitance-voltage study of silicon-on-insulator structure with an ultrathin buried SiO2 layer fabricated by wafer bonding

A silicon-on-insulator (SOI) structure with a thin (typically 20 nm) Si lay er and an ultrathin (2 nm) thermally grown buried SiO2 layer, which is a ke y structure in novel Si devices, was fabricated in our laboratory by a wafe r bonding technique. Transmission electron microscope observation revealed that the ultrathin buried oxide layer is continuous and uniform in thicknes s. For the SOI samples, the effect of direct carrier tunneling through the buried oxide was studied by capacitance-voltage (C-V) measurements. The res ultant C-V characteristics were found to be determined by the tunneling pro bability of carriers through the buried oxide, and band bending in the SOI layer