GaN Semiconductor Device Integrating High-Voltage Switches and Control Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing gallium nitride semiconductor devices face challenges in reducing circuit size and operating effectively at high temperatures, with limitations in integration and noise issues due to separate semiconductor switches and control circuits, and the inability of Si semiconductor elements to function above 200°C.
Innovation Solution
A gallium nitride semiconductor device with a first and second semiconductor layer, where the first layer has an insulating region between high and low withstand voltage semiconductor elements, allowing for reduced circuit size and high-temperature operation, and a method involving epitaxial growth to integrate high and low withstand voltage elements in a single device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate semiconductor switches and control circuits are used, then each component can function independently, but the total circuit size increases and noise issues arise
Solution Approach 1:
The patent combines the semiconductor switch and control circuit into a single integrated device structure. The control circuit is formed in the same gallium nitride semiconductor layer as the semiconductor switch, allowing both functions to coexist in one compact unit. This integration reduces the total circuit size while maintaining independent functionality of each component through spatial separation within the integrated structure.
2Ease of manufacture
If Si semiconductor elements are used, then the device can be manufactured with existing technology, but the device cannot operate above 200°C
Solution Approach 1:
The patent changes the material parameter from silicon to gallium nitride, which fundamentally alters the temperature capability. Gallium nitride has a wider bandgap and higher thermal stability, enabling operation at temperatures exceeding 200°C. This material parameter change maintains ease of manufacture through established gallium nitride growth techniques while dramatically improving the maximum operating temperature.
3Area of stationary object
If multiple semiconductor elements are integrated in a single device, then circuit size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the integrated device into distinct functional regions: a first region containing the semiconductor switch and a second region containing the control circuit. These segments are formed in different areas of the same gallium nitride semiconductor layer, allowing independent design and manufacturing of each function while achieving integration. The segmentation reduces manufacturing complexity compared to fully monolithic integration.
4Loss of energy
If gallium nitride semiconductor elements are used, then power loss is reduced and switching speed is improved, but the device complexity increases compared to Si elements
Solution Approach 1:
The gallium nitride semiconductor layer serves multiple functions simultaneously: it forms both the high-voltage semiconductor switch and the low-voltage control circuit. This multi-functionality reduces the need for separate material layers and structures that would otherwise be required, thereby reducing overall device complexity despite the advanced material system. The universal gallium nitride layer provides both power handling and control functions.
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 significantly reduces circuit size, enables high-temperature operation, minimizes power loss, and lowers production costs by integrating high and low withstand voltage elements in a single device, while maintaining high channel mobility and reducing unnecessary components.
Implementation Method 1
a first conductivity type first GaN layer and a second conductivity type second GaN layer which are laminated in this order on a surface of a semiconductor substrate
Data Source
AI summary
An insulating layer, an undoped first GaN layer and an AlGaN layer are laminated in this order on a surface of a semiconductor substrate. A surface barrier layer formed by a two-dimensional electron gas is provided in an interface between the first GaN layer and the AlGaN layer. A recess (first recess) which reaches the first GaN layer but does not pierce the first GaN layer is formed in a surface layer of the AlGaN layer. A first high withstand voltage transistor and a control circuit are formed integrally on the aforementioned semiconductor substrate. The first high withstand voltage transistor is formed in the first recess and on a surface of the AlGaN layer. The control circuit includes an n-channel MOSFET formed in part of the first recess, and a depression type n-channel MOSFET formed on a surface of the AlGaN layer. In this manner, there are provided a gallium nitride semiconductor device which can be used under a high temperature environment while reduction in total circuit size can be attained, and a method for producing the gallium nitride semiconductor device.