Electrical characterization of highly reliable 8 nm oxide

Device scaling down requires the decreasing of any thermal treatment in order to reduce dopant diffusion. The possibility of using steam oxides grown at low temperatures to substitute dry thermal oxides for tunnel application in flash memory is investigated here comparing different technologies: standard dry/steam and N2O nitrided dry/steam oxides. A direct comparison in terms of oxide defect level and breakdown characteristics is presented, also considering the charge trapping behavior of area and periphery capacitors. A correlation between residual charge trapping and intrinsic reliability of these oxides is also presented, showing that the overall best performances are obtained by the nitrided oxides. The nitridation of steam oxide at high temperature results in good charge trapping characteristics, comparable with those of a nitrided dry oxide; at the same time charge-to-breakdown improves, while the defect level decreases. In the investigated thickness range even the nitridation of a steam oxide at low temperature resulted in a suitable dielectric for tunnel application in flash memories.