Amorphous Metal Oxide Bilayers to Avoid Sneak‐Path Currents for High‐Density Resistive Memory Arrays

Resistance switching devices are potential candidates for future memory applications. However, sneak-path current issues in crossbar array cause energy and heat dissipation, and it requires additional circuitry for mitigation. To address this, we introduce a hybrid device with functional oxide as bilayer of amorphous strontium titanium oxide (a-STO) and vanadium oxide (a-VOx). Highperformance resistive switching material a-STO is coupled with a-VOx having fast apolar threshold switching. The hybrid device gives performance equivalent to conventional one resistance switch and one selector architecture with stability of 6000 endurance cycles. Non-linearity factor of the hybrid device is 4.8, which is slightly higher than only a-STO device of 4.7. Using I–V measurements, readout margin is calculated, which suggests integration into 104 104 array when 10% readout margin is considered at switching ratio of 8. Further, the selector effect using non-zero-crossing property of memristors, which reveals six times reduction in OFF current in the hybrid device, is quantified. Compositional analysis along the device cross-section to understand elemental distribution and interface effects of two unique, multifaceted oxides is presented. As such, in the hybrid structure non-linearity factor remains nearly constant, while the absolute value of non-zero-crossing current is reduced six times, which can reduce the overall sneak current in crossbars.