Enhancing device reliability in Pt/Ti/Al2O3/p-Ge metal-oxide-semiconductor memcapacitor via CF4 plasma treatment of Ge

Reliable modulation of artificial synapse device is crucial for the implementation of neuromorphic computing systems. Herein, we first demonstrated the reliable Ge-based memcapacitor which is enabled by Al₂O₃/Ge interface engineering based on CF₄ plasma treatment. Capacitance measurements show improved linearity and cycle-to-cycle variations in CF₄ plasma-treated memcapacitor, proving reliable synaptic modulation. The improvement in the synaptic behavior of the CF₄ plasma-treated memcapacitor is attributed to the reduction in Al₂O₃/Ge interface defect states by F-passivation on Ge surface. Low interface trap density, extracted using the high-low capacitance-voltage technique, and a relatively low contact potential difference, measured by Kelvin probe force microscopy, verify the reversible charge trapping and de-trapping via precisely controlled defect states within a narrow depletion region. This study highlights the potential of CF₄ plasma treatment as a successful strategy for enhancing the reliability of memcapacitors, paving the way for advanced neuromorphic computing technologies.