Excess silicon at the silicon nitride/thermal oxide interface in oxide-nitride-oxide structures

The chemical composition and structure of Si3N4/thermal (native and wet) Si O2 interface in oxide-nitride-oxide structures are studied by using seconda ry ion mass spectroscopy, electron energy loss spectroscopy (EELS) and Auge r electron spectroscopy (AES) measurements. EELS and AES experiments show t he existence of excess silicon at the Si3N4/thermal SiO2 interface. Excess silicon (Si-Si bonds) at Si3N4/SiO2 interface exists in the form of Si-rich silicon oxynitride. Numerical simulation of the Si-Si bond's electronic st ructure by using semiempirical quantum-chemical method (MINDO/3) shows that Si-Si defects act as either electron or hole traps. This result explains t he abnormally large electron and hole capturing at this interface reported earlier. (C) 1999 American Institute of Physics. [S0021-8979(99)03418-0].