Coplanar-Gate Synaptic Transistor Array With Organic Electrolyte Using Lithographic Process

The artificial neural networks based on biomimetic synaptic devices attempts to process and memorize information by simulating a human brain. Electrolyte-gated transistors (EGTs) are promising candidates for artificial synaptic devices, due to their large specific capacitance, low operating voltage, and sensitive interfacial properties. Although large-scale EGTs array based on inorganic electrolytes and small-scale EGTs arrays based on organic electrolytes are reported, large-scale EGTs arrays based on organic electrolytes have not yet been focused. In this work, a large-scale EGTs array ( $10\times10$ ) based on coplanar-gate structure using lignin as electrolyte is fabricated. The organic dielectric layer fabricated in the last step can be protected from the damage caused by wet etching, thus providing an opportunity for the application of other organic electrolytes in the large-scale EGTs array. Lignin exhibits good electric performance and is environment-friendly due to its renewable property. The synaptic properties of single transistor in the EGTs array, such as excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), and high-pass filtering are realized. The real-time learning and forgetting procedures stimulated by different spike numbers of EGTs array are also demonstrated.