Synaptic device

A synaptic device comprising:

• a substrate;
• a channel layer on the substrate;
• a gate dielectric layer on the channel layer;
• and
• a gate electrode on the gate dielectric layer,
• wherein the gate dielectric layer comprises a charge supply dielectric film and a piezoelectric film,
• wherein the charge supply dielectric film comprises a metal oxide or a metal sulfide,
• wherein the piezoelectric film comprises a piezoelectric material that converts a pressure stimulation into an electrical signal,
• wherein accordance to a change in a signal applied to the gate electrode, a magnitude and aspect of a current flowing through the channel layer are changed, and
• wherein the gate electrode is in direct mechanical contact with a top surface of the piezoelectric film,
• wherein the gate electrode, the piezoelectric film, the charge supply dielectric film and the channel layer overlap each other,
• wherein the gate electrode is disposed at a higher level than a level of the piezoelectric film,
• wherein a content of oxygen of the metal oxide is greater than, or less than, a stoichiometric amount, and
• wherein a content of sulfur of the metal sulfide is greater than, or less than, a stoichiometric amount.