(Invited) Hafnium oxide based CMOS compatible ferroelectric materials

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/cm2 and a high coercive field of about 1 MV/cm was observed. Doping of HfO2 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.