Ferroelectric Memcapacitor on SOI for High Capacitive Ratio by Mechanism of Depletion Capacitance Modulation Toward Dimension Scaling Down

A C_HCS/C_LCS ratio of 500× for a ferroelectric capacitive memory (FCM) with an SOI substrate has been demonstrated as an ideal synaptic operation achievement. This ratio is a crucial parameter in FCM as it indicates the ability of the memory to store and retrieve data reliably. The modulated depletion region could be expanded laterally due to the spatial restriction in the vertical direction by the SOI to reduce C_LCS; moreover, a low-voltage-based saturation capacitance of double Hf_1-xZr_xO₂ (DHZO) further enhanced C_HCS. For DHZO-SOI FCMs, the outstanding nondestructive read operation (NDRO) was experimentally exhibited with >10⁹ cycles by both devices and readout schemes, α_P/α_D = -0.25 / +1.55 for synapse. The proposed technique is simulated with a remaining ratio of 73× for pillar FCM scaling to 20nm, a promising concept that benefits the dimension scaling pathway.