An anomalous correlation between gate leakage current and threshold voltage fluctuation in advanced MOSFETs

An anomalous correlation of gate leakage current and threshold voltage fluctuation in aggressively scaled MOSFETs is revealed and analyzed by statistical technique and a corresponding physical model is proposed. For a range of threshold voltage (V
_t
) design, gate leakage at fixed gate and drain bias increases with V
_t
before it decreases at higher V
_t
. The behavior can be accurately explained by a trade-off between two mechanisms (“two reversed functions”): V
_t
roll-off effect and gate leakage current density dependence on surface potential.