Nitride Semiconductor Structure for High Breakdown and High Current
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Solution Overview
Problem
Conventional nitride semiconductor devices face challenges in achieving both high breakdown voltage and high current operation simultaneously.
Innovation Solution
A nitride semiconductor device is designed with a substrate, first and second nitride semiconductor layers of different conductivities, an electron transport layer, an electron supply layer, a gate electrode, a source electrode, and a drain electrode, where at least part of the second nitride semiconductor layer is fixed to a potential different from the source electrode, and a high-resistance layer is used to separate and insulate the nitride semiconductor layers, allowing for controlled depletion layers and channel narrowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional nitride semiconductor device structure is used, then high breakdown voltage can be achieved, but high current operation cannot be achieved simultaneously
Solution Approach 1:
The device is divided into multiple functional regions: a first conductivity type nitride semiconductor layer for high breakdown voltage, a second conductivity type nitride semiconductor layer for current conduction, and a high-resistance layer for isolation. This segmentation allows each region to optimize for its specific function, resolving the contradiction between breakdown voltage and current capability
Solution Approach 2:
Different regions of the device are assigned different conductivity types and resistance characteristics. The first nitride semiconductor layer has high resistance for voltage blocking, while the second nitride semiconductor layer has low resistance for current conduction. This local differentiation enables simultaneous achievement of high breakdown voltage and high current operation
2Productivity
If the second nitride semiconductor layer is fixed to the source electrode potential, then high current operation is improved, but breakdown voltage decreases
Solution Approach 1:
A high-resistance layer is introduced as an intermediary between the second nitride semiconductor layer and the source electrode. This intermediary layer isolates the second layer from the source electrode potential, preventing direct electrical connection while allowing controlled interaction through depletion layer formation, thus maintaining both high current and high breakdown voltage
3Strength
If depletion layers are expanded for high breakdown voltage, then channel narrowing occurs reducing current operation
Solution Approach 1:
The device structure segments the depletion layer formation into two distinct areas: depletion layers formed at the interface between the first and second nitride semiconductor layers for voltage blocking, and a separate channel region for current conduction. This spatial segmentation allows depletion layers to expand for high breakdown voltage without significantly narrowing the current channel
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 the nitride semiconductor device to achieve high breakdown voltage and high current operation by controlling depletion layers and channel narrowing, thereby enhancing both turn-off and turn-on characteristics.
Implementation Method 1
an electron transport layer and an electron supply layer disposed along inner surfaces of the first opening
Implementation Method 2
at least part of the second nitride semiconductor layer is fixed to a potential that is different from a potential applied to the source electrode
Data Source
AI summary
Nitride semiconductor device includes: a substrate; a first nitride semiconductor layer of a first conductivity above the substrate; a second nitride semiconductor layer of a second conductivity different from the first conductivity, above the first nitride semiconductor layer; a first opening penetrating through the second nitride semiconductor layer; an electron transport layer and an electron supply layer disposed along inner surfaces of the first opening, in stated sequence from the substrate-side; a gate electrode above the electron supply layer, covering the first opening; a source electrode connected to the electron supply layer and the electron transport layer, at a position separated from the gate electrode; and a drain electrode on a surface of the substrate opposite to a surface on which the first nitride semiconductor layer is disposed. At least part of the second nitride semiconductor layer is fixed to a potential different from a potential of the source electrode.