<p>Short Communication: An Updated Design to Implement Artificial Neuron Synaptic Behaviors in One Device with a Control Gate</p>

Abstract

Background: As a key component in artificial intelligence computing, a transistor design is updated here as a potential alternative candidate for artificial synaptic behavior implementation. However, further updates are needed to better control artificial synaptic behavior. Here, an updated channel-electrode transistor design is proposed as an artificial synapse device; this structure is different from previously published designs by other groups. Methods: A semiconductor characterization system was used in order to simulate the artificial synaptic behavior and a scanning electron microscope was used to characterize the device structure. Results: It was found that the electrode added to the transistor channel had a strong impact on the representative transmission behavior of such artificial synaptic devices, such as excitatory postsynaptic current (EPSC) and the paired-pulse facilitation (PPF) index. Conclusion: These behaviors were tuned effectively and the impact of the channel electrode is explained by the combined effects of the joint channel electrode and conventional gate. The voltage dependence of such oxide devices suggests more capability to emulate various synaptic behaviors for numerous medical and non-medical applications. This is extremely helpful for future neuromorphic computational system implementation.

Artificial Neuron Synaptic Realization of One Device with Transparent and Environmentally Friendly Materials

“…The EPSC reached a peak value and decreased gradually, which is similar to the nonlinear transmission characteristics of a biological synapse. As a fitting line shown in Figure 4d, the decay of EPSC can be described by a stretched exponential function 19…”

“…EPSC response is the most basic and typical activity signal of biological synapses. At present, many oxide thin-film transistors have been used to simulate the artificial synaptic behavior, This representative artificial synaptic transmission behavior is due to the mobile carriers in the amorphous oxide, which depends on the oxide components − and is similar to those in cation transport among neurons. According to FTIR results, i-PU ion gels contain a large number of imino groups (−NH).…”

“…The EPSC reached a peak value and decreased gradually, which is similar to the nonlinear transmission characteristics of a biological synapse. As a fitting line shown in Figure d, the decay of EPSC can be described by a stretched exponential function where I 0 is the triggered current, τ is the retention time, t 0 is the time when the presynaptic spike finishes, I ∞ is the postsynaptic current at the end of the presynaptic spike, and τ is estimated to be ∼10 s. Energy efficiency is one of the most important characteristics of neuromorphic devices. The energy consumption ( P ) of the spike event can be estimated from the relation below where U , I peak , and t are read voltage, peak EPSC value, and spike duration time, respectively.…”

“…There are mainly two-terminal and three-terminal electronic devices, which could be used as the artificial synaptic devices to mimic the artificial synaptic behaviors. − However, the three-terminal devices are regarded to be superior to the two-terminal devices due to their better controllability with the combined effects of the gate voltage and drain voltage controls. , Transistors and capacitors could be used to emulate a single synapse, , and the presynaptic spikes could be emulated with the gate or drain pulse voltages applied. In recent years, there have been a lot of advanced materials, such as low-dimensional materials and amorphous oxide materials, employed to implement artificial synaptic devices. , Amorphous oxide transistors have attracted much attention due to their good properties, including low-temperature fabrication conditions not higher than 200 °C, transparency, and fairly good electrical properties. , The carriers such as ions in the materials facilitate the mimicking of artificial synapses, the working mechanisms of which may also involve the transfer of carriers such as ions. − Here, a new type of organic material ionic polyurethane (i-PU) is used as the channel of thin-film transistors, which is not only transparent and easy to fabricate with low-temperature processing but also environmentally friendly . Synaptic behaviors implemented by this organic material are investigated for the first time in our present devices.…”

“…8,9 Amorphous oxide transistors have attracted much attention due to their good properties, including low-temperature fabrication conditions not higher than 200 °C, transparency, and fairly good electrical properties. 10,11 The carriers such as ions in the materials facilitate the mimicking of artificial synapses, the working mechanisms of which may also involve the transfer of carriers such as ions. 12−14 Here, a new type of organic material ionic polyurethane (i-PU) is used as the channel of thin-film transistors, which is not only transparent and easy to fabricate with low-temperature processing but also environmentally friendly.…”