The ferroelectric behavior of capacitors based on hafnium oxide dielectrics will be reported. Thin films of 6-30 nm thickness were found to exhibit ferroelectric polarization-voltage hysteresis loops when integrated into TiN-based metal-insulator-metal capacitors. A remanent polarization up to 25 μC/cm~2 and a high coercive field of about 1 MV/cm was observed. Doping of HfO_2 by different dopants with an atomic radius ranging from 110 nm (Si) to 188 nm (Gd) was evaluated and in all cases ferroelectric behavior was verified by P-V hysteresis, small signal capacitance-voltage, and for Si by piezoelectric measurements. Polarization retention showed no significant decay within a measurement range of up to two days.
展开▼
