Ultra-thin fully-depleted SOI MOSFETs: Special charge properties and coupling effects

Abstract

A standard characterization method in fully depleted SOI devices consists in biasing the back interface in the accumulation regime, and measuring the front-channel properties. In ultra thin body device however, it is sometimes no longer possible to achieve such an accumulation regime at the back interface. This unusual effect is investigated by detailed simulations and analytical modelling of the potential and electron/hole concentrations. The enhancement of the interface coupling effect in ultra thin body devices, called super-coupling, can explain previously published experimental data [Pretet J, Ohata A, Dieudonne F, Allibert F, Bresson N, Matsumoto T, et al. Scaling issues for advanced SOI devices: gate oxide tunneling, thin buried oxide, and ultra-thin films. In: 7th International symposium silicon nitride and silicon dioxide thin insulating films, Paris, France, 2003. Electrochemical Society Proceedings, vol. 2003-02, Pennington (USA); 2003. p. 476–87], and reveals new challenges in the characterization of advanced SOI devices.