Oxide Semiconductor Power Device for Normally-Off Low Resistance
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Solution Overview
Problem
Conventional power devices with wide band gaps, such as SiC or GaN, face challenges in achieving a normally-off state with low resistance, as they are either complex to manufacture or result in increased power consumption, and existing solutions complicate the device structure and increase costs.
Innovation Solution
A semiconductor device with a power element that includes a switching field-effect transistor configuration using i-type or substantially i-type oxide semiconductor layers for the channel region, allowing for both on and off states without increasing power consumption, by applying different voltages to the gate electrodes, and incorporating a power MOSFET with multiple gates and insulating layers to manage carrier concentration and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an electron concentration is reduced to obtain a normally-off power device, then the device can be turned off, but the resistance of the element is increased
Solution Approach 1:
The patent changes the material parameter from conventional semiconductor to oxide semiconductor, which fundamentally alters the electrical characteristics. The oxide semiconductor layer provides a normally-off state with low resistance by utilizing its unique band structure and carrier concentration properties, resolving the trade-off between turn-off capability and resistance
Solution Approach 2:
The patent employs a composite structure combining oxide semiconductor layer with other functional layers (electrode layers, insulating layers). This composite material approach allows simultaneous achievement of normally-off characteristic and low resistance by optimizing the interface properties and composition of each layer
2Ease of operation
If an innovative structure is used to realize a normally-off device, then a normally-off state can be achieved, but the device structure becomes complicated and manufacturing cost is increased
Solution Approach 1:
The patent extracts the channel-forming function to a specifically designed oxide semiconductor layer, which inherently provides the normally-off characteristic. This eliminates the need for complex additional structures or mechanisms that would otherwise be required to achieve normal off-state in conventional power devices
Solution Approach 2:
By changing the fundamental material parameter to oxide semiconductor, the patent achieves normally-off state as an inherent property rather than requiring complex structural modifications. This material parameter change simplifies the overall device structure while maintaining the desired electrical characteristics
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 enables a power device that can be turned on or off efficiently without increased power consumption, maintaining low resistance and simplifying the device structure, thereby addressing the complexity and cost issues of existing technologies.
Implementation Method 1
a switching field-effect transistor for applying first voltage to the gate of the power element
Implementation Method 2
A node of the first gate and the second gate of the power MOSFET is connected to the switching field-effect transistors, and a channel region of each of the switching field-effect transistors is formed using an i-type or substantially i-type oxide semiconductor layer
Data Source
AI summary
The semiconductor device includes a power element which is in an on state when voltage is not applied to a gate, a switching field-effect transistor for applying first voltage to the gate of the power element, and a switching field-effect transistor for applying voltage lower than the first voltage to the gate of the power element. The switching field-effect transistors have small off-state current.