Solid-State Electrolyte FET Layout for Low-Voltage Synaptic Switching
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Solution Overview
Problem
Existing synaptic transistors based on electric double layer or red-ox technologies either require high working voltages and multiple terminals or suffer from low conductance range, on/off ratio, and low endurance.
Innovation Solution
A lithium-based solid-state electrolyte-based field effect transistor with a three-terminal configuration, comprising a dielectric layer, source and drain electrodes, and a gate electrode positioned between them, utilizing a lithium-based solid-state electrolyte layer without a semiconductor layer, achieving low working voltage, high on/off ratio, and wide conductance range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric double layer transistor structure is used, then conductance range and on/off ratio are improved, but working voltage increases and device complexity increases
Solution Approach 1:
The patent extracts and removes the semiconductor layer from the traditional electric double layer transistor structure, creating a direct interface between the electrolyte layer and dielectric layer. This simplification eliminates the need for high working voltages while maintaining the beneficial conductance range and on/off ratio characteristics.
Solution Approach 2:
The patent employs a composite structure combining electrolyte layer, dielectric layer, and metal electrodes without requiring a semiconductor layer. This composite material approach enables low working voltage operation while preserving high conductance range and on/off ratio performance.
2Use of energy by moving object
If red-ox transistor structure is used, then working voltage is reduced and device complexity is decreased, but conductance range and on/off ratio deteriorate
Solution Approach 1:
The patent introduces an electrolyte layer as an intermediary between the gate electrode and the channel formation region. This electrolyte mediator enables low working voltage operation through ionic conduction while simultaneously achieving high conductance range and on/off ratio by controlling ion distribution in the absence of a semiconductor layer.
Solution Approach 2:
The patent changes the fundamental operating parameter from electronic conduction in semiconductors to ionic conduction in electrolytes. This parameter change enables low working voltage operation while achieving superior conductance range and on/off ratio through electrochemical field effects.
3Reliability
If electric double layer transistor structure is used, then conductance range and on/off ratio are improved, but device complexity and terminal count increase
Solution Approach 1:
The patent removes the back gate terminal from the traditional four-terminal electric double layer transistor structure, simplifying it to a three-terminal device. This extraction maintains the high conductance range and on/off ratio while reducing device complexity and terminal count.
Solution Approach 2:
The gate electrode in the patent's three-terminal structure performs multiple functions: it controls the electrochemical field, regulates ion distribution, and modulates channel conductance. This multi-functionality eliminates the need for a separate back gate terminal while maintaining superior electrical characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The transistor operates with low working voltage, high on/off ratio, and wide conductance range, exhibiting high endurance and compatibility with spiking neural networks.
Implementation Method 1
a lithium-based solid-state electrolyte layer between and on top of the source electrode and the drain electrode
Implementation Method 2
When a potential is applied to the gate electrode G, charges will move inside the electrolyte EC and produce an electric field in the semi-conductor layer SC
Data Source
AI summary
An electrolyte-based field effect transistor includes a dielectric layer; a source electrode and a drain electrode located on top of the dielectric layer; the electrolyte-based transistor further including an electrolyte layer between and on top of the source electrode and the drain electrode, the part of the electrolyte layer located between the source electrode and the drain electrode being in direct contact with the dielectric layer; and a gate electrode on top of the electrolyte layer, the orthogonal projection of the gate electrode in a plane including the source and drain electrodes being located, at least in part, between the source and the drain electrodes.