Two-stage drain leakage degradation in sub-micron MOSFET technology

Gate Induced Drain Leakage (GIDL) current is increasingly important in thin-oxide MOSFETs. Results are reported here on the degradation of the drain leakage current, I/sub DL/, in scaled nMOSFETs under hot carrier stress. A two-stage degradation process is observed where /spl Delta/I/sub DL/ increases with time initially at a rate /spl prop/t/sup 0.5/ followed by a second regime with rate /spl prop/t/sup 3/. The initial phase is driven by interface traps N/sub it/ which induce trap-assisted tunneling (TAT), while the second phase is caused by trapped oxide charge which eventually leads to a catastrophic increase in GIDL through band-to-band tunneling (BET). The superlinear BBT-induced degradation rate implies a potentially severe reliability constraint for future thin-oxide devices.