Impact of area scaling on the ferroelectric properties of back-end of line compatible Hf0.5Zr0.5O2 and Si:HfO2-based MFM capacitors

Scaling of planar HfO2-based ferroelectric capacitors is investigated experimentally by varying the capacitor area within five orders of magnitude, under the scope of a limited thermal budget for crystallization. Both Hf0.5Zr0.5O2 (HZO) and Si-doped HfO2 (HSO)-based metal/ferroelectric/metal capacitors with a 10nm dielectric film thickness and TiN electrodes are demonstrated to be ferroelectric when integrated in a back-end of line (BEOL) of 130nm CMOS technology, with a maximum thermal budget below 500 degrees C. When the area of the ferroelectric capacitors is scaled down from 7850 mu m(2) to 0.28 mu m(2), no degradation of the remanent polarization (2.P-R > 10 mu C/cm(2) for HSO, > 30 mu C/cm(2) for HZO) or of the switching kinetics (down to 100ns at 3V) is observed. Significant improvement of the field cycling endurance is demonstrated upon area scaling, consistent with the reduction of the total number of defects when devices are shrunk. The results pave the way for future BEOL demonstrations in 130nm and more advanced nodes with record endurance similar to perovskite ferroelectrics.

Automated summary

The study investigated the scaling of planar HfO2-based ferroelectric capacitors under a limited thermal budget for crystallization, demonstrating that HZO and HSO-based metal/ferroelectric/metal capacitors integrated in 130nm CMOS technology are ferroelectric. The results show no degradation of remanent polarization or switching kinetics when the area of the ferroelectric capacitors is scaled down. Additionally, there is a significant improvement in field cycling endurance with area scaling, indicating potential for future BEOL demonstrations in advanced nodes with record endurance.