Remote carrier trapping in FinFETs with ONO buried layer: Temperature effects

The charge trapping mechanisms are studied at room and high temperature in advanced SOI FinFETs fabricated on SiO2-Si3N4-SiO2 (ONO) multi-layer buried insulator (BOX). By applying appropriate back-gate and/or drain bias, the buried nitride layer can trap charges. The coupling mechanism between front and back interfaces enables the front-channel drain current to reflect the presence or absence of trapped/injected charges in the BOX. In this work, the charge trapping/detrapping is induced by a constant drain or back-gate bias or during the scanning of the back-gate voltage. According to the polarity of the trapped charges and their location along the channel, various current levels are observed leading to a memory effect. In order to clarify the charge trapping and coupling mechanisms, the temperature of operation was used as additional experimental parameter. The amount of trapped charges depends not only on the bias conditions but also on temperature and fin geometry. We discuss the 3D coupling effects between the channel and the remote trapped charges.