High-Density and Near-Linear Synaptic Device Based on a Reconfigurable Gated Schottky Diode

A reconfigurable gated Schottky diode is proposed as new high-density and low-power synaptic device that has near-linear changes in conductance. The device has a reverse current of less than 12 nA/μm and an effective device area of 6F
²
. Since the Al/poly-Si Schottky junction is located on the bottom gate, which has a SiO
₂
/Si
₃
N
₄
/SiO
₂
charge trap layer, the effective Schottky barrier height is modulated by the bottom gate bias or by the amount of charge trapped in the Si
₃
N
₄
layer. The Schottky reverse current has an exponential relationship with the effective Schottky barrier height associated with the amount of stored charge, and the amount of stored charge is logarithmically proportional to the number of potentiation pulses. Because the exponential and logarithmic relationships cancel each other out, a near-linear conductance response to the number of potentiation pulses is obtained from the proposed device.