Oxide Semiconductor Storage Circuit for Power-Stop Data Retention
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Solution Overview
Problem
Existing semiconductor storage devices require data to be saved and returned between volatile and nonvolatile storage devices when power supply voltage is stopped and resumed, leading to inefficiencies.
Innovation Solution
A semiconductor storage device is designed with cascade-connected storage circuits, using transistors with semiconductor layers containing oxide semiconductors and capacitors to hold data signals without separation, allowing potential control through data potential holding and control circuits for capacitive coupling, eliminating the need for data transfer between devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is stored separately in volatile and nonvolatile storage devices, then data can be retained when power is stopped, but data must be saved and returned between devices when power is stopped and resumed
Solution Approach 1:
The patent combines volatile and nonvolatile storage functions into a single integrated storage device. The storage circuit includes both a capacitor (for volatile storage) and a transistor with oxide semiconductor layer (for nonvolatile storage) in the same circuit unit, eliminating the need for separate volatile and nonvolatile storage devices and their associated data transfer operations.
Solution Approach 2:
The storage device performs multiple functions within a single integrated circuit: it can store data volatilely during operation, retain data nonvolatilely when power is stopped, and automatically restore data without manual save/return operations. The same storage circuit handles both volatile and nonvolatile storage functions.
2Reliability
If separate volatile and nonvolatile storage devices are used, then data can be retained without power, but operational complexity increases due to save and return operations
Solution Approach 1:
By integrating volatile and nonvolatile storage functions into a single storage circuit, the patent eliminates the need for separate save and return operations between devices. The unified storage device automatically maintains data continuity without requiring manual intervention or complex operational sequences.
3Speed
If volatile storage is used for high-speed data access, then writing speed is improved, but data is lost when power supply voltage is stopped
Solution Approach 1:
The storage circuit merges the high-speed access capability of volatile storage (capacitor-based) with the data retention capability of nonvolatile storage (oxide semiconductor transistor-based). The capacitor enables fast write operations while the oxide semiconductor transistor maintains data retention, achieving both high speed and reliability in a single integrated structure.
Solution Approach 2:
The storage device uses composite material structures combining different semiconductor materials: standard semiconductors for high-speed operation and oxide semiconductors for data retention. This material composition allows the device to simultaneously achieve fast writing speed and reliable data retention without power.
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
Enables data retention and output without electric charge leakage, allowing continuous operation when power supply voltage is stopped and resumed, reducing power consumption and operational complexity.
Implementation Method 1
a storage circuit in each stage includes a transistor including a semiconductor layer containing an oxide semiconductor and a capacitor
Implementation Method 2
the data potential control circuit can control the potential of the data signal held in the wiring without leaking electric charge by capacitive coupling through the capacitor
Data Source
AI summary
A semiconductor storage device which stops and resumes the supply of power supply voltage without the necessity of saving and returning a data signal between a volatile storage device and a nonvolatile storage device is provided. In the semiconductor storage device, data is held in a data holding portion connected to a transistor including a semiconductor layer containing an oxide semiconductor and a capacitor. The potential of the data held in the data holding portion is controlled by a data potential holding circuit and a data potential control circuit. The data potential holding circuit can output data without leaking electric charge, and the data potential control circuit can control the potential of the data held in the data holding portion without leaking electric charge by capacitive coupling through the capacitor.