피로현상을 고려한 강유전 게이트 MFSFET 소자의 특성

초록

Changes of device characteristics of the metal-ferroelecric-semiconductor FET (MFSFET) with the progress of fatigue of the ferroelectric thin film are simulated in this study. The field-dependent polarization model and the square-law FET model are employed in our simulation. In the simulation of switching, the relative switched charge before fatigue is assumed as 0.74 nC, which reduces to 0.15 nC when the thickness of the oxygen layer becomes 50 Å after progress of fatigue. C-VG curves generated from the MFSFET model exhibit the accumulation, the depletion and the inversion regions clearly. They also exhibit the memory window of 2 V. ID-VD curves are composed of the triode and the saturation regions. The difference of saturation drain currents of the MFSFET device at the dual threshold voltages in ID-VD curve is 6 mA/cm2, which decreases as much as 50 % after fatigue. Our simulation model is expected to be very useful in the estimation of the behaviour of MFSFET devices.