Interface-Trap Analysis by an Optically Assisted Charge-Pumping Technique in a Floating-Body Device

An optically assisted charge-pumping (CP) technique is proposed for the characterization of interface traps in floating-body (FB) devices. Even without a body contact, majority carriers can be supplied into the FB by light illumination, which contributes to enabling the CP process. Under a strong inversion enabled by a back gate, the front gate triggers the CP process with a designed pulse waveform. Consequently, modulation of the majority-carrier concentration at the front interface is monitored by the change of the drain current. Thus, the interface-trap density is extracted from the monitored drain current and the developed analytical model.