Studies of Interface States of Silicon Metal-Oxide-Semiconductor Devices by Dynamic Conductance and Noise Measurements and Effects of Bias-Temperature Stresses

Abstract

Dynamic conductance measurements in metal-oxide-semiconductor (MOS) capacitors and the effects of bias-temperature stresses are considered together with noise measurements to determine the origin of 1/f noise in an MOS field effect transistor (MOSFET) operated either under subthreshold or above threshold conditions. The 1/f noise in a subthreshold MOSFET is shown to be due to the dispersion of dielectric loss of the interfacial oxide. The source of 1/f noise in the inversion regime is less certain. Both the number fluctuation model and the mobility fluctuation model are consistent with the data of the bias-temperature treatment effect on 1/f noise reported by Vandamme and Dik provided that the data are interpreted in the reconstructing interface states model. Further inference from conductance data tends to favor the mobility fluctuation model. It is also pointed out that there is only one microscopic model that provides a unified mechanism which gives not only the dispersive dielectric loss and the 1/f noise at subthreshold but also the mobility fluctuations at inversion.