Oxide Semiconductor Transistor Circuit for Low Off-State Charge Loss
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Solution Overview
Problem
Conventional semiconductor devices experience impaired drive capability due to off-state current, leading to loss of electric charge at the gate of transistors, which affects the amplitude voltage of output signals.
Innovation Solution
The semiconductor device incorporates transistors with channel regions formed using an oxide semiconductor layer, achieving an off-state current of 1 nA/μm or less, thereby reducing charge loss and enhancing drive capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transistors are used in semiconductor devices, then the device can operate with standard manufacturing processes, but off-state current causes loss of electric charge at the gate, impairing drive capability
Solution Approach 1:
The patent changes the material parameter of the transistor channel from conventional semiconductor to oxide semiconductor, which fundamentally alters the off-state current characteristics. This material substitution enables the transistor to achieve off-state current of 1 aA/μm or less, directly resolving the charge loss problem while maintaining drive capability.
Solution Approach 2:
The patent employs oxide semiconductor material as a composite solution for the channel region, combining the benefits of semiconductor functionality with the ultra-low off-state current properties of oxide materials. This composite approach allows simultaneous achievement of low power consumption and high reliability.
2Reliability
If the gate of the first transistor is kept in floating state to maintain amplitude voltage equal to power supply voltage, then capacitive coupling can be realized, but the second transistor connected to the gate must be turned off, causing charge loss over time
Solution Approach 1:
By changing the material of the second transistor to oxide semiconductor, the off-state current is reduced to 1 aA/μm or less, enabling the gate to maintain its floating state without significant charge loss. This allows the second transistor to remain off while preserving the amplitude voltage stability required for capacitive coupling operation.
3Reliability
If oxide semiconductor transistors are used to reduce off-state current, then drive capability and charge retention are improved, but manufacturing complexity may increase
Solution Approach 1:
The patent focuses on changing the material parameter to oxide semiconductor, which can be integrated into existing semiconductor manufacturing processes through established techniques such as sputtering and annealing. This approach achieves ultra-low off-state current while minimizing increases in manufacturing complexity.
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 use of oxide semiconductor transistors with low off-state current improves the drive capability and extends the time the potential can be maintained at desired levels, allowing for a broader range of drive frequencies and reduced power consumption.
Implementation Method 1
A channel region is formed using an oxide semiconductor layer in each of the first transistor and the second transistor. The first transistor and the second transistor have an off-state current of 1 aA/μm or less.
Data Source
AI summary
An object is to improve the drive capability of a semiconductor device. The semiconductor device includes a first transistor and a second transistor. A first terminal of the first transistor is electrically connected to a first wiring. A second terminal of the first transistor is electrically connected to a second wiring. A gate of the second transistor is electrically connected to a third wiring. A first terminal of the second transistor is electrically connected to the third wiring. A second terminal of the second transistor is electrically connected to a gate of the first transistor. A channel region is formed using an oxide semiconductor layer in each of the first transistor and the second transistor. The off-state current of each of the first transistor and the second transistor per channel width of 1 μm is 1 aA or less.