On uniformity challenges and mitigation strategies of low thermal budget ferroelectric devices for memory and neuromorphic applications

Abstract

Thin film ferroelectric devices with ultralow power operation, non-volatile data retention with fast and reliable switching are attractive for non-volatile memory and as synaptic weight elements. However, low thermal budget ferroelectric oxides suffer from crystalline inhomogeneity and defects that make their large-scale circuit integration challenging. Here, we report on thermally engineered wafer-scale homogeneity in Hf0.5Zr0.5O2 capacitors, which improves device reliability. By comparing samples with different thermal treatments during both the film growth and crystallization phases, through electrical, structural and modelling analysis, the results show that a higher ALD temperature of 285°C will provide more uniform polarization distribution, but with the downside of increased leakage current, compared to a growth temperature of 200 oC. This is attributed to the larger grain size observed after the full fabrication process in high temperature deposited films. This work provides a pathway to accelerate the integration of ferroelectric HZO into ultralow power memory and neuromorphic computing hardware.