THE CORRELATION BETWEEN GATE CURRENT AND SUBSTRATE CURRENT IN 0.1-MU-M NMOSFETS

The correlation between gate and substrate currents in NMOSFET's with effective channel length, L(eff), down to 0.1 mu m is investigated within the general framework of the lucky-electron model. It is found that the correlation coefficient, Phi(b)/Phi(i), decreases with decreasing L(eff) in the 0.1 mu m regime, where Phi(b) is the effective Si-SiO2 barrier height for channel hot-electrons, and Phi(i) is the effective threshold potential for impact ionization. Furthermore, this effect becomes stronger in NMOSFET's with shorter L(eff). These experimental results suggest the need for further investigation on specific assumptions in the lucky-electron model to understand hot-electron behavior and impact ionization-mechanisms in 0.1 mu m-scale NMOSFET's.