Oxygen-Scavenging-Driven Interlayer Engineering for Balancing Linearity and Retention in IGZO Synaptic Memristors

초록

IGZO-based memristors exhibit analog synaptic behavior through Schottky barrier modulation, but the trade-off among update linearity, dynamic range, and retention governed by interlayer design remains unclear. Here, we comparatively investigated Pd/IGZO/SiO2/p+-Si (Sample #1) and Pd/IGZO/AlOX/Al (Sample #2) memristors with naturally formed interlayers induced by different bottom-electrode stacks. Sample #1 exhibited a V O-rich IGZO layer and soft-broken SiO2 interlayer, resulting in larger conductance and superior retention (tau = 3.9 & times; 104 s). In contrast, the preserved AlOX interlayer in Sample #2 enabled voltage-division-assisted linear weight updates (alpha P = 1.2, alpha D = 0.8) while maintaining near-unity linearity under stronger programming conditions. Neural-network simulations further revealed a linearity-retention trade-off, where Sample #2 showed faster initial learning, whereas Sample #1 achieved higher peak recognition accuracy (92% vs. 88%). These results highlight oxygen-scavenging-based interlayer engineering as an effective strategy for balancing linearity and retention in IGZO synaptic memristors.

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