Synthesis of Amorphous-Crystalline Mixture Boron Nitride for Balanced Resistive Switching Operation.

Two-dimensional boron nitride (BN) insulating layers gained attracted attention for their high-performance memristive behavior. However, crystalline hexagonal BN (h-BN) suffers from a high initial SET voltage due to a lack of boron vacancies, while vacancy-rich amorphous BN (a-BN) exhibits significant current fluctuations during RESET due to stochastically formed filaments. In this work, an amorphous-crystalline mixture BN (acm-BN) via low-pressure chemical vapor deposition to achieve balanced resistive switching, offering low SET voltage and improved RESET stability is synthesized. High-resolution transmission electron microscopy reveals that BN films grown at 930 °C are predominantly amorphous, with crystalline phases increasing at higher temperatures, resulting in homogeneous crystalline areas with partial amorphous regions at 990 °C. This structure in acm-BN allows low-voltage filament formation through the localized a-BN regions during the SET process and sharp rupture of the confined filament during the RESET process. Consequently, acm-BN exhibits a lower breakdown voltage (3-5 V) during the initial SET cycle compared to h-BN (9.2 V) and stable RESET cycles and long retention times exceeding 10 000 s, while a-BN exhibits significant fluctuations and short retention. Furthermore, acm-BN exhibits better long-term potentiation linearity (non-linearity factor β = 1.4), enabling higher learning efficiency (87.26%) compared to a-BN (β = 4.8, 63.86%).