Hole tunneling current through oxynitride/oxide stack and the stack optimization for p-MOSFETs

A systematic study on hole-tunneling current through both oxynitride and oxynitride/oxide (N/O) stack is for the first time presented based on a physical model. The calculations are in good agreement with the available experimental data. With a given equivalent oxide thickness (EOT), and under typical operating gate voltages (|Vg|<2 V), hole-tunneling current (essentially the gate current) is found to be lowest through the oxynitride or N/O stack with /spl sim/33% of nitrogen (N). An optimized N/O stack structure with 33% (atomic percentage) nitrogen and with a 3 /spl Aring/ oxide layer for keeping acceptable channel interface quality is proposed to project the N/O gate dielectrics scaling limit using in MOSFETs.