Organic FeFET Memory Array for Non-Destructive Readout
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Solution Overview
Problem
Existing semiconductor memories, particularly ferroelectric random access memories (FRAM), face challenges due to high temperature processing requirements and expensive inorganic materials, as well as the destructive readout issue, which complicates data storage and retrieval in organic electronic devices.
Innovation Solution
A non-volatile memory array using ferroelectric field-effect transistors (FeFET) with organic thin-film transistors, employing a single ferroelectric and organic dielectric layer, allows for low-cost, low-voltage organic electronic devices by utilizing ink jet printing for electrode and semiconductor structures, enabling addressable reading and writing without disturbing adjacent pixel data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ferroelectric thin film based memories (FRAM) are used, then non-volatility and fast write speed are achieved, but destructive readout occurs requiring pre-charge operations
Solution Approach 1:
The patent introduces a ferroelectric field-effect transistor (FeFET) as an intermediary device between the ferroelectric memory cell and the read circuitry. The FeFET uses the ferroelectric layer as its gate dielectric, allowing the polarization state to control the channel conductivity without directly reading the ferroelectric cell, thereby avoiding destructive readout while maintaining non-volatility
2Reliability
If standard ferroelectric FET memory cells are used, then non-destructive readout is achieved, but high temperature processing (>600°C) is required
Solution Approach 1:
The patent changes the material parameters by using organic semiconductor materials and solution-processing techniques instead of traditional inorganic materials and high-temperature vacuum deposition. This allows the ferroelectric FET to be fabricated at temperatures below 200°C while maintaining the necessary ferroelectric properties and device functionality
Solution Approach 2:
The patent employs low-cost organic semiconductor materials and simple solution-based fabrication processes (such as spin-coating or inkjet printing) instead of expensive inorganic materials and complex high-temperature processing equipment, making the technology economically viable for large-scale production
3Temperature
If inorganic raw materials are used for memory fabrication, then high temperature processing capability is achieved, but material cost and processing cost increase
Solution Approach 1:
The patent replaces expensive inorganic raw materials (such as silicon, metal oxides requiring vacuum deposition) with inexpensive organic semiconductor materials that can be processed from solution. This dramatically reduces both material costs and equipment requirements, enabling low-cost manufacturing
Solution Approach 2:
The patent substitutes complex mechanical vacuum deposition systems with simple solution-based deposition methods (spin-coating, dip-coating, or inkjet printing). This eliminates the need for expensive vacuum chambers and high-temperature furnaces, simplifying the manufacturing process and reducing costs
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 solution facilitates the production of low-cost, non-destructive readout organic electronic devices, such as RFID and sensor data loggers, with improved data storage capabilities and reduced processing costs, using ferroelectric polymer thin films and organic semiconductor materials.
Implementation Method 1
Ferroelectric materials possess the unique properties of a spontaneous polarization which can be re-oriented with an applied field, and that the polarization state can be retained even after the removal of electric field
Implementation Method 2
When a gate voltage is applied, the polarization of the ferroelectric thin film can be either positive or negative and the polarization state can be retained after the removal of gate voltage. This positive or negative polarization can affect the source-drain current or the source-drain resistance
Data Source
AI summary
An organic non-volatile memory array including multiple pixels and associated signal lines that are disposed on and between a substrate, a single ferroelectric dielectric layer, and a single organic dielectric layer, where each pixel includes a ferroelectric field-effect transistor (FeFET) and at least one organic thin-film field effect transistor (FET) that are connected to associated signal lines in a way that facilitates addressable reading and writing to the FeFET of a selected pixel without disturbing the data stored in adjacent pixels. Analog data storage in the FeFET array is also introduced that does not require analog-to-digital conversion of the stored data.