A new technique for characterization of thin-film ferroelectric memory devices

Pulse switching and hysteresis measurements are commonly employed to characterize thin-film ferroelectric materials. Capacitance-voltage (C-V) techniques have found wide applications in semiconductor technology to determine interface trap charge in silicon metal-oxide-semiconductor devices. C-V measurements made on potassium nitrate (KNO3) thin-film memory devices at high frequency (1 MHz) with slow ramp rates (200–2000 mV/s) are reported here for the first time. The C-V plots are integrated to determine the quantity of displaced charge during switching. These data are compared with the corresponding results from pulse and hysteresis measurements. The effect of ramp rate on the C-V measurements suggests mobile charge (ion) migration under bias. The fatigue problem in the device structures is explained by means of buildup of charge at KNO3/contact interfaces during continuous switching. © 1988, American Vacuum Society. All rights reserved