Non-volatile Latch Circuit Using Oxide Semiconductor Transistors
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Solution Overview
Problem
Non-volatile latch circuits using ferroelectric elements face issues with reliability of rewrites and voltage reduction, requiring high-accuracy reading circuits due to small remanent polarization, which increases variation and complexity.
Innovation Solution
A non-volatile latch circuit with a loop structure using transistors with oxide semiconductor channels and a capacitor for data retention, where the transistors have low off-state current and high on-state current, allowing data to be retained even after power is turned off, and read easily when power is restored.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a ferroelectric element is used as a non-volatile logic circuit, then data retention without power is achieved, but reliability of rewrites and voltage reduction are problematic
Solution Approach 1:
The invention changes the material parameter from ferroelectric to oxide semiconductor, fundamentally altering the mechanism of data retention. The oxide semiconductor transistor maintains logic states through its ability to retain charge in the off-state, achieving non-volatility without the rewrite reliability issues of ferroelectric materials.
Solution Approach 2:
The oxide semiconductor transistor acts as a disposable switching element that can be easily replaced or reprogrammed. The simple structure and ease of manufacturing allow for high-yield production, compensating for the individual component's limited operational life through mass production and replacement.
2Duration of action of stationary object
If a ferroelectric element is used, then non-volatile storage is achieved, but high-accuracy reading circuits are needed due to small remanent polarization
Solution Approach 1:
The invention extracts the data retention function from the transistor itself rather than relying on a separate ferroelectric element. The oxide semiconductor transistor inherently retains charge in its off-state, eliminating the need for additional ferroelectric components and simplifying the overall circuit structure.
Solution Approach 2:
The oxide semiconductor transistor serves multiple functions: it acts as both the switching element and the data storage element. This multi-functionality reduces the total number of components needed and simplifies the reading circuitry, as the transistor's own state can be directly read without complex detection circuits.
3Duration of action of stationary object
If remanent polarization is small in ferroelectric elements, then non-volatile storage is achieved, but variation increases and high-accuracy reading is needed
Solution Approach 1:
The invention changes the fundamental parameter used for data storage from remanent polarization to charge retention in the oxide semiconductor. This parameter change eliminates the variation issues associated with ferroelectric polarization, as the oxide semiconductor's charge retention characteristics are more uniform and less sensitive to manufacturing variations.
4Speed
If conventional transistors are used, then fast switching is achieved, but data cannot be retained after power is turned off
Solution Approach 1:
The invention changes the semiconductor material from conventional silicon to oxide semiconductor, fundamentally altering the electrical characteristics. The oxide semiconductor's unique property of maintaining an off-state with extremely low leakage current allows the transistor to retain its state indefinitely without power, while maintaining fast switching capabilities when powered.
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 solution provides a reliable and stable non-volatile latch circuit that operates over a wide temperature range, retains data with low variation, and reduces power consumption by allowing logic states to be stored and restored quickly and efficiently.
Implementation Method 1
A transistor using an oxide semiconductor as a semiconductor material of a channel formation region is used as a switching element, and a capacitor is provided to be electrically connected to a source electrode or a drain electrode of the transistor, whereby data of the latch circuit can be retained
Implementation Method 2
a capacitor is provided to be electrically connected to a source electrode or a drain electrode of the transistor, whereby data of the latch circuit can be retained
Data Source
AI summary
A novel non-volatile latch circuit and a semiconductor device using the non-volatile latch circuit are provided. The latch circuit has a loop structure in which an output of a first element is electrically connected to an input of a second element and an output of the second element is electrically connected to an input of the first element through a second transistor. A transistor using an oxide semiconductor as a semiconductor material of a channel formation region is used as a switching element, and a capacitor is provided to be electrically connected to a source electrode or a drain electrode of the transistor, whereby data of the latch circuit can be retained, and a non-volatile latch circuit can thus be formed.