Effect of Substrate Implant Tuning on the Performance of MFIS Silicon Doped Hafnium Oxide (HSO) FeFET Memory

摘要

Improved characteristics of ferroelectric Si:HfO2 (HSO) MFIS FeFETs by tuning the substrate implant doping concentration is reported. Shallow implant doping gives the possibility to control the FeFET readout range, whereas the deep implant affects the Ioff current, resulting in a higher Ion-Ioff current ratio. Additionally, the implant tuning improves the switching MFIS field distribution enabling lower FeFET switching voltages. A transition from a charge trap dominated endurance to an endurance that is limited by the interface trap generation is observed when the substrate implant is tuned. An endurance of 10⁵ cycles with approximately 4 orders of magnitude Ion-Ioff residual current ratio is measured on the FeFET devices. The impact of tuning shallow and deep substrate implant profiles is studied with respect to changes of the MFIS stack characteristics and overall FeFET performance.