Dual-Gate Oxide Transistor Threshold and Current Control
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Solution Overview
Problem
It is challenging to simultaneously control the threshold voltage and increase the current value in oxide semiconductor transistors, as existing dual-gate structures require switching the same back gate, making it difficult to achieve both objectives effectively.
Innovation Solution
A semiconductor device with a novel structure featuring a first gate and a second gate with a channel formation region in between, where the second gate is electrically connected to the first gate through a capacitor, allowing control voltage to be supplied to the second gate during off-states and using voltage changes based on the first gate's voltage during on-states to enhance current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a dual gate structure is used to increase current value, then the current value in conduction state can be efficiently increased, but it becomes difficult to control the threshold voltage simultaneously because the same back gate is used and connection needs to be switched
Solution Approach 1:
The patent divides the gate function into two independent gates: a front gate for controlling threshold voltage and a back gate for enhancing current value. This segmentation allows each gate to perform its specific function independently without requiring switching connections, resolving the contradiction between current enhancement and threshold voltage control.
Solution Approach 2:
The back gate is designed to serve multiple purposes: it can be connected to the front gate through a capacitor to provide voltage amplification during conduction state, while also allowing independent threshold voltage control when disconnected. This multi-functionality enables the system to achieve both high current value and precise threshold control without structural modification.
2Power
If the back gate is connected to the front gate to increase current value, then the current value can be efficiently increased, but the ability to control threshold voltage independently is lost
Solution Approach 1:
The patent implements a dynamic connection mechanism where the back gate can be selectively connected to or disconnected from the front gate through a switching element. During conduction state, the connection is established to amplify current; during threshold control state, the connection is disconnected to enable independent voltage control. This dynamic reconfiguration resolves the contradiction between current enhancement and control versatility.
Solution Approach 2:
A capacitor is introduced as an intermediary element between the front gate and back gate. This capacitor enables voltage transfer and amplification from the front gate to the back gate while allowing independent control of the back gate voltage when needed. The intermediary component facilitates both current enhancement and threshold control without direct permanent connection.
3Adaptability or versatility
If switching is required to change back gate connection for different functions, then both threshold control and current enhancement can be achieved, but device complexity increases due to switching mechanisms
Solution Approach 1:
The patent combines the threshold control and current enhancement functions into a unified dual-gate transistor structure where both gates are inherently present and can be controlled independently or together. This merging eliminates the need for separate switching mechanisms to change connection configurations, as the independent gate structure naturally supports both functions simultaneously or sequentially without additional 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
This configuration enables both threshold voltage control and increased current value, improving the reliability and electric characteristics of the transistor, particularly in oxide semiconductor devices.
Implementation Method 1
The second gate is electrically connected to the first gate through a capacitor
Data Source
AI summary
Provided is a semiconductor device including a transistor in which a first gate and a second gate are provided with a channel formation region provided therebetween and which achieves both control of the threshold voltage and an increase in the on-state current. In a period during which first voltage with which the transistor is turned off is supplied to the first gate, control voltage for controlling the threshold voltage is supplied to the second gate. In a period during which second voltage with which the transistor is turned on is supplied to the first gate, the second voltage is supplied to the first gate and voltage in which voltage based on change in the voltage of a signal supplied to the first gate is added to the control voltage is supplied to the second gate.