Percolating Source Layer for Low-Voltage OFET Memory
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving low write and erase voltages while maintaining fast reading speeds and stable hysteresis characteristics, particularly in organic field-effect transistors (OFETs) due to limitations in charge injection mechanisms and material compatibility.
Innovation Solution
The semiconductor device incorporates an electrically percolating source layer, such as a dilute network of carbon nanotubes, a memory layer with charge storage materials like benzocyclobutene, and a Schottky barrier configuration that allows direct charge injection from the source layer to the memory layer, reducing the reliance on the semiconducting channel for voltage control and enhancing hysteresis characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional charge injection mechanisms are used in organic field-effect transistors, then device structure is simple, but write and erase voltages are high and hysteresis characteristics are unstable
Solution Approach 1:
An electrically percolating source layer is introduced as an intermediary between the electrode and the semiconducting channel. This source layer, composed of materials such as carbon nanotubes, metallic nanowires, or conductive polymers, enables direct charge injection into the memory layer while maintaining electrical continuity, thereby reducing the voltages required for write and erase operations and stabilizing hysteresis characteristics.
Solution Approach 2:
The source layer utilizes composite material structures, such as dilute networks of carbon nanotubes or combinations of metallic and semiconducting nanowires, which provide both electrical conductivity and controlled charge injection properties. These composite materials enable efficient charge transfer to the memory layer without requiring high voltages, resolving the contradiction between energy consumption and reliability.
2Use of energy by moving object
If direct charge injection from source layer to memory layer is implemented, then write and erase voltages are reduced, but device complexity increases
Solution Approach 1:
The device is segmented into distinct functional layers: an electrically percolating source layer, a memory layer with charge storage materials, and a semiconducting channel layer. This segmentation allows each layer to perform its specific function efficiently, with the source layer handling charge injection and the memory layer storing charges, thereby reducing the overall voltages required while maintaining manageable device complexity through clear functional separation.
3Productivity
If carbon nanotube network is used as source layer, then charge injection efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The manufacturing process utilizes parameter changes, specifically controlling the concentration and distribution of carbon nanotubes in the source layer to achieve the desired electrical percolation threshold. By adjusting parameters such as nanotube density, length, and spatial distribution, efficient charge injection is achieved without requiring extremely precise manufacturing control, as the system tolerates a range of parameter values that maintain percolation and conductivity.
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
This configuration enables lower write and erase voltages, faster reading speeds, and improved ON/OFF current ratios, along with enhanced hysteresis stability, making the device suitable for both memory and transistor applications with reduced power consumption and increased flexibility in material selection.
Implementation Method 1
The source layer is an electrically percolating layer such as, e.g., a dilute network of carbon nanotubes (CNTs), a layer of graphene, a dilute network of metallic and/or semiconducting nanowires, or a layer of a conductor, semiconductor, or semi-metal including perforations
Implementation Method 2
The semiconductor device is configured to utilize a field effect controlled Schottky barrier at the interface between the source layer and the semiconducting channel layer in order to turn the device on and off
Implementation Method 3
a memory layer with charge storage materials like benzocyclobutene
Data Source
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AI summary
Various embodiments are provided for semiconductor devices including an electrically percolating source layer and methods of fabricating the same. In one embodiment, a semiconductor device includes a gate layer, a dielectric layer, a memory layer, a source layer, a semiconducting channel layer, and a drain layer. The source layer is electrically percolating and perforated. The semiconducting channel layer is in contact with the source layer and the memory layer. The source layer and the semiconducting channel layer form a gate voltage tunable charge injection barrier.