Understanding of hard and soft breakdown phenomena in thin gate oxides through carrier transport properties after breakdown

The carrier separation technique is applied to gate oxides after the occurrence of soft and hard breakdown. The dominant carrier type in leakage current flow through gate oxides after breakdown is identified for MOSFETs with different channel types and doping types of the poly Si gate electrode. The systematic approach through this combination of carrier separation measurement and MOSFETs with various doping types is shown to be quite effective in studying the conduction mechanism and the physical picture of breakdown spots.