Degradation mechanisms of organic ferroelectric field-effect transistors used non-volatile memory

Abstract

Organic ferroelectric field-effect transistors were fabricated for use as non-volatile memory that retained 50% of current hysteresis over seven days. Hysteresis degradation was shown to originate from reductions in semiconductor mobility, dielectric capacitance, and shifts in transistor threshold voltages. The mobility decrease and the threshold-voltage shift were caused by dipolar alignment in the ferroelectric insulator, and the rate of change in gate capacitance is explained by the depolarization field in the ferroelectric dielectric. A method to calibrate and extract the input switching voltage is presented, and this calibration accounts for polarization loss with time and allows the ferroelectric transistors to be used as analog memories.