DIFFERENCE BETWEEN THE 1/F NOISE SPECTRAL DENSITY BEFORE AND AFTER STRESS AS A MEASURE OF THE SUBMICRON MOS-TRANSISTORS DEGRADATION

The paper deals with the 1/f noise as a measure of the submicron MOS transistor degradation. As the reference point of the investigations has been assumed the plot of the 1/f noise drain voltage spectral density S-VD versus the channel length L of the long-channel device which in log-log scale is linear (1/L) at slope equals -1. A theoretical analysis and experimental investigations indicate that before stress decrease of the carrier effective mobility, when the MOS transistors channel becomes shorter, causes deviate down of the plot S-VD vs. L in comparison with the extrapolated linear plot of the long channel device. During stress the hot electron effect leads to the out of controll generation of additional interface states near drain edge which influence on deviate up of the plot S-VD vs. L in comparison with the value before stress. The measure of the degradation due to the hot-electron effect is difference between S-VD after and before stress. It is showed that S-VD of the extrinsic transistors do not dependent on the parasitic resistances therefore the considerations concern both of the conventional and LDD-MOS devices. Moreover the fundamental conditions of the measurement have been determined