Transition from partial to full depletion in advanced SOI MOSFETs: Impact of channel length and temperature

This paper presents a detailed investigation of short-channel effects in advanced partially depleted SOI NMOSFETs. The influence of the back-gate voltage on the threshold voltage reveals the increase of the coupling effect with the channel length. The channel length impact is reversed by using pocket implants. Then SOI devices from the same wafer can behave as fully or partially depleted according to the channel length. This effective doping mechanism is amplified at low temperature operation. Systematic measurements show that long channel transistors become fully depleted before short channels, in particular when decreasing the temperature. The reduction of the channel length or the increase of the back-gate voltage and temperature attenuate the gate-induced floating body effect.