Characterization of tunneling current and breakdown voltage of advanced CMOS gate oxide

Scaling down of the CMOS technology requires ultra thin oxide to meet the scaling of gate length. Gate oxide reliability becomes important as the gate oxide thickness is reduced. Tunneling current that flow through the thin oxide will cause an increase of the off-state current leakage and unnecessary power dissipation. In this study, probing is performed either directly on the silicided poly top-plate or on the Al interconnect top plate MOS capacitor. Probing directly on the silicided poly top plate, capacitor shows poorer contact between the tungsten probe needles and the silicide. We found that the optimal probe needle pressure had to be used to obtain consistent result. This paper studies the tunneling current mechanisms through the oxide and also the soft breakdown and hard breakdown of the oxide. Our baseline flow now utilizes probing directly on silicide which has greatly improved the costs and cycle time of this testing.