Correlative analysis of embedded silicon interfaces passivation by “Kelvin probe force microscopy” and “corona oxide characterization of semiconductor”

    We report a correlative analysis between corona oxide characterization of semiconductor (COCOS) and Kelvin probe force microscopy (KPFM) for the study of embedded silicon-oxide interfaces in the field of chemical and field-effect passivation. Analyzed parameters by these measurements are linked to different factors and specifically to defects density of embedded silicon-dielectric interfaces, surface band bending or the distribution of charges in the nearest surface volume. Furthermore, this COCOS-KPFM correlative analysis turns out to be a useful method to access to chemical and field-effect passivation. We confirm that it is possible to differentiate the influence of local band bending on sample passivation (i.e. field effect passivation) from the effects due to the local recombination rates (i.e. chemical passivation). The measurements were carried on five different passivation layers, precisely, 10.5 nm-thick SiO 2 , 50 nm-thick SiN, 7nm-thick Al 2 O 3 , 7 nm-thick HfO 2 and double layer of 7 nm-thick Al 2 O 3 below 53 nm-thick Ta 2 O 5 . This correlative analysis indicates that HfO 2 present to be the best chemical passivation and SiN is the worst case in term of field effect passivation for p-type silicon. Additionally, we confirm that Ta 2 O 5 layer on top of Al 2 O 3 increase the defects density.