Residual Interface Traps at Bird's Beaks of Field Oxide Layers

The interface trap density ( D it ) of field oxide films is determined from the subthreshold characteristics of parasitic field effect transistors. A D it of 8×10 14 m -2 eV -1 persists in the bird's beak regions of local oxidation of silicon (LOCOS) structure after annealing at 723 K in a H 2 ambient. This value is almost ten times larger than that observed for a SiO 2 /Si interface grown on a (100) Si plane.