Tunneling current noise in thin gate oxides

Abstract

We have examined fluctuations in the tunneling current of 3.5 nm SiO2 barriers for voltages in the direct tunneling regime. We find a 1/f power law for the spectral density of the fluctuations where f is the frequency. This 1/f noise can be attributed to fluctuations of a trap assisted tunneling current through the oxide that causes current noise but is not evident in the I–V curves. We suggest that this noise may be a more sensitive probe of trap assisted tunneling and degradation in thin oxides than other measures. At voltages above a threshold of 2.5 V, we observe the reversible onset of non-Gaussian current transients in the noise. The onset of these current transients can be related to a transition in the spacial uniformity of the tunneling current density that may result in eventual breakdown of the oxide.

Effect of Schottky barrier alteration on the low-frequency noise of InP-based HEMTs

“…For higher currents, an dependence is observed with and is explained by the influence of the Schottky barrier's series resistance. Assuming that the LF barrier height fluctuations are caused by trap assisted tunnelling, in analogy with the case of thin silicon oxides [12], we interpret this significant reduction in LF gate current noise as being caused by a strong reduction of the density (or trap parameters) of the effective tunnelling defects. At the same time, the lower ideality factor of the 60% Al containing structure in the Schottky layer also contributes to the reduction of the LF gate current noise.…”

Noise modeling for RF CMOS circuit simulation

“…Several authors have observed noise in the gate current [48]- [50]. Alers [48] has attributed this to the phenomenon of trap-assisted tunneling.…”

Silicon Field Emitter Arrays

“…Thus simple molecular adsorption does not appear to provide a complete explanation for the change in emission. Very similar fluctuations also occur in solid-state devices (e.g., MOS structures) where adsorption cannot occur, and have been explained as changes in interface (oxide) charge [77].…”