Electron spin resonance of inherent and process induced defects near the Si/SiO2 interface of oxidized silicon wafers

Major point defects, inherent and process induced, near the Si/SiO2 interface of metal–oxide–silicon structures have now been identified by electron spin resonance. The most pervasive defect is the Pb center, a trivalent silicon atom bonded to the Si at the interface, with dangling orbital aimed into the SiO2 (e.g., .Si≡Si3). The Pb orbital is the source of about one‐half of the electrical interface traps (density Dit) in as‐oxidized or radiation‐ or injection‐damaged Si. Concentration of Pb is dependent on oxidation and other thermal treatments, and is a sensitive gauge of interface physicochemical disposition. Radiationlike processing methods—ion implantation, rapid thermal annealing, plasma etching, and electron‐beam lithography—generate additional point defects, including charged E’ centers (O3≡Si. . . . +Si≡O3), nonbridging oxygen hole centers (O3≡Si–O. . . . H–O–Si≡O3), peroxy radicals (O3≡Si–O–O. . . . Si≡O3) in the oxide, and D centers (.Si≡Si3)n in the silicon. Subsequent thermochemical treatment...