Thin Film Transistor Nonvolatile Memory via Self-Heating Carrier Storage
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Solution Overview
Problem
Conventional methods for using thin film transistors (TFTs) as nonvolatile memory are complex and costly, and as components miniaturize, data retention issues arise due to the need for additional semiconductor processes and thinner tunneling oxides.
Innovation Solution
A method that utilizes self-heating in TFTs to store carriers by manipulating electrical characteristics, allowing for writing and erasing operations without additional semiconductor processes, by applying specific voltages to induce electron-hole pairs and separate them within the TFT body, thereby integrating TFTs as nonvolatile memory units on a shared substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods add floating gate or tunneling oxide to TFT structure for carrier storage, then nonvolatile memory function is achieved, but manufacturing process complexity increases and cost increases
Solution Approach 1:
The patent extracts and eliminates the need for additional floating gate or tunneling oxide structures by utilizing the inherent body region of the conventional TFT. The method stores carriers directly in the body through self-heating effect, removing complex additional layers while achieving nonvolatile memory function.
Solution Approach 2:
The TFT uses its own body region and self-heating effect to store carriers, rather than requiring external additional structures. The existing TFT components serve the dual purpose of switching and memory storage functions.
2Length of moving object
If tunneling oxide is formed thinner for component miniaturization, then device size is reduced, but data retention capability deteriorates
Solution Approach 1:
The patent uses the body region of the TFT, which is already present and does not require additional thin-film formation processes. This approach avoids the limitations of thin tunneling oxide while achieving carrier storage through the self-heating effect in the body.
3Reliability
If additional semiconductor manufacturing processes are added for nonvolatile memory integration, then nonvolatile memory function is achieved, but manufacturing cost increases
Solution Approach 1:
The patent makes the conventional TFT serve dual functions as both a switching device and a nonvolatile memory cell. By utilizing the body region for carrier storage through self-heating, the same TFT structure performs both logic and memory functions without requiring separate memory device fabrication.
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 approach simplifies the manufacturing process, reduces costs, and maintains data retention by eliminating the need for floating gates or tunneling oxides, enabling efficient integration of nonvolatile memory with other TFT components on an LCD panel.
Implementation Method 1
When the TFT is turned on to cause the self-heating effect and generate electron-hole pairs
Implementation Method 2
when a Joule Heat resulted by the gate voltage and the first drain voltage is enough to cause the self-heating effect
Implementation Method 3
the vertical electric field on the gate separates the electron-hole pairs and injects the carriers to the body of the TFT
Implementation Method 4
when a potential difference between the second drain voltage and the source voltage is enough to make the majority carriers stored in the body overcome the energy barrier in grain boundary of the body
Data Source
AI summary
The present invention relates to a nonvolatile memory apparatus and a method of using a thin film transistor (TFT) as a nonvolatile memory by storing carriers in a body of the TFT, which operates a general TFT as a memory cell of a nonvolatile memory by manipulating the electrical characteristics of the TFT in order to integrate with other electrical components formed by TFTs, such as logic circuit or TFT-LCD pixel transistor, on the LCD panel without additional semiconductor manufacturing processes.