Quantum two-dimensional calculation of time constants of random telegraph signals in metal-oxide-semiconductor structures

The thermal and gate-voltage dependencies for the capture and emission times of random telegraph signals have been theoretically analyzed in a Si-SiO2 interface. A quasi-two-dimensional treatment of the interaction between a neutral near-interface oxide trap and an electron in the subband of the inversion layer has been developed to obtain expressions for the capture and emission times where the influence of the trap parameters (energy depth, distance to the interface, and electron-phonon coupling factor) is clearly shown. This analysis combines multiphonon-emission theory, tunnel transition probability and the electrostatic Coulomb barrier effect, allowing us to reproduce experimental data for traps in different devices, temperatures, and bias conditions. As a result, trap distances to the interface, trap energy levels, and electron-phonon couplings have been calculated. The character of single electron transitions in this process let us show that the ground and first excited subbands, with similar capture and emission times, are the most important contributors to the phenomenon.