Process-Induced Point Defects in Oxidized Silicon Structures

ABSTRACTPoint defects caused by common fabrication methods may increase device susceptibility to radiation or hot carriers. In this study, defects induced by dry and wet oxidation, ion implantation, and rapid thermal annealing are examined by electron paramagnetic resonance. A brief 02 anneal at 900°C is found to be more effective than N2 in transformation of a steam-grown oxide interface to that of a dry oxide. A N2 anneal at 450 °C has little effect, and must be extended to about 2 hr to dessicate the interface. Implants of B, P, and BF2 have no direct effect on the interface, but activation anneal in N2 at 900°C produced large Pb concentration. Implant generates E′ centers in the oxide, which are eliminated by the activation. Rapid thermal annealing below 600°C reduces interface traps, but increases them above 700°C, with severe oxide and interface damage at 1100 °C. Electron-beam lithography and plasma- or ion-beam etching are discussed briefly.