Hysteresis Effects in FinFETs with ONO Buried Insulator

FinFETs fabricated on SiO2-Si3N4-SiO2 (ONO) buried insulator are investigated for flash memory application. The Si3N4 layer can trap charges by tunneling at high back-gate bias. The amount of trapped charges is sensed, via gate coupling effects, by the drain current. The trapped charges in Si3N4 layer also induce a drain current hysteresis when the back-gate is dynamically scanned. Systematic measurements reveal that the charge trapping and drain current hysteresis are useful memory effects. The memory window depends on bias conditions and geometrical parameters.