Atomic Layer Deposition Plasma-Based Undoped-HfO2 Ferroelectric FETs for Non-Volatile Memory

A plasma-based undoped-HfO 2 FeFET (ferroelectric FET) with non-volatile memory characteristics is demonstrated. Modifying the O 2 plasma period in plasma-enhanced atomic layer deposition (PE-ALD) is an effective approach to enhance the remnant polarization ( \text{P}_{\text {r}} ) up to 2P _{\text {r}} = 25\,\,\mu \text{C} /cm 2 for the MFM (metal/ferroelectric/metal) structure with ferroelectric undoped-HfO 2 thin films, and successful integration is implemented for the FeFET. The appropriate O 2 vacancies ( \text{V}_{\text {o}}^{{2}+} ) benefit the formation of the ferroelectric phase since they play the role of dopants and help orthorhombic phase (o-phase) formation during post-metal annealing (PMA). The \text{V}_{\text {o}}^{{2}+} -rich undoped-HfO 2 FeFET exhibits a memory window (MW) of 0.5 V, {5} \times {10}^{{4}} switching endurance cycles, and higher than 10^{{4}} sec of data retention with \text{V}_{\text {P/E}} = \pm 5 V.