Paramagnetic defects in annealed ultrathin layers of SiOx, Al2O3, and ZrO2 on (100)Si

Electron spin resonance (ESR) measurements on (100)Si∕SiOx∕ZrO2 and (100)Si∕Al2O3∕ZrO2 stacks with nm-thick dielectric layers reveal, upon postdeposition oxidation (PDO) in the range of 650–800°C, the appearance of various SiO2-characteristic defects, including E′ and EX centers and a 95-G doublet. These defects generally grow during PDO treatment, attesting to significant modification of the SiOx interlayer, and∕or additional SiOx interlayer growth. The ESR results on E′ indicate that the SiOx interlayer formed in (100)Si∕SiOx∕ZrO2 is drastically inferior to standard thermal (100)Si∕SiO2, exhibiting over one order of magnitude more O-deficiency centers. The (100)Si∕Al2O3 system appears more robust in terms of SiOx interlayer growth, and has better interlayer properties.