Long-Term Depression Mimicked in an IGZO-Based Synaptic Transistor

Amorphous indium-gallium-zinc oxide-based synaptic transistors with hafnium oxide (HfOx) insulating layer were fabricated to mimic synaptic long-term depression (LTD) characteristics. The fabrication temperature was less than 120°. Interval time of presynaptic spikes-dependent synaptic depression was first demonstrated in these IGZO-based synaptic transistors, which is important for computation system coding by time. The depression effect in our synaptic transistor is erasable, using ultraviolet light ($\lambda = 365$ nm) to erase the electrons trapped in the defects of the HfOx layer. Our device is in great significance for future brain-like artificial neuromorphic computation system since LTD has been verified as a contributor to learning and memory function in brains.