Low-frequency noise overshoot in ultrathin gate oxide silicon-on-insulator metal–oxide–semiconductor field-effect transistors

Abstract

A noise overshoot phenomenon occurring in the ohmic regime is described in fully depleted and partially depleted silicon-on-insulator metal–oxide–semiconductor field-effect transistors with 2.5 nm nitrided gate oxide. It is characterized by a peak in the current noise spectral density S1 versus the front gate voltage VGS, whereby the peak amplitude can be several orders of magnitude higher than the background 1/f noise. In addition, it is shown that the corresponding spectrum has a Lorentzian shape. Associated with this noise peak is a second maximum in the device transconductance. It is believed that the mechanism of this excess noise is similar as for the kink-related noise overshoot, found in saturation. However, the origin of this floating-body effect is believed to be related to electron valence-band tunneling through the thin dielectric and occurring for a sufficiently large gate voltage.