Semiconductor Device with Reverse-Blocking Heterojunction Diode
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Solution Overview
Problem
The manufacturing process of semiconductor devices with reverse-blocking capabilities is complex due to the need for deep trench etching and deep diffusion layers to suppress leakage current, particularly at the element edge portions.
Innovation Solution
A semiconductor device is designed with a switching mechanism and a reverse-blocking heterojunction diode formed on the same semiconductor body, utilizing a P+-type hetero semiconductor region on the back side to simplify the peripheral structure and reduce the thickness of the drain region, eliminating the need for deep trench etching and diffusion layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep trench etching and deep diffusion layers are used to suppress leakage current, then reverse-blocking characteristics are improved, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent extracts the reverse-blocking function from the peripheral isolation structure and relocates it to the main surface through a dedicated reverse-blocking diode structure. This separates the reverse-blocking function from the complex deep trench etching and deep diffusion processes, allowing the main surface to focus on switching functionality while the reverse-blocking diode handles reverse current suppression.
Solution Approach 2:
The patent transitions from vertical reverse-blocking (requiring deep trench etching into the substrate) to a surface-level reverse-blocking implementation using a heterostructure diode formed on the main surface. This dimensional shift from depth-based isolation to surface-based functional integration simplifies the manufacturing process while maintaining reverse-blocking performance.
2Object-generated harmful factors
If deep diffusion layers are used for junction isolation, then leakage current is suppressed, but manufacturing time and process steps increase
Solution Approach 1:
The reverse-blocking diode structure is formed using the same heteroepitaxial growth process that creates the main device layers, allowing the reverse-blocking functionality to be integrated automatically during the standard manufacturing sequence without requiring separate deep diffusion or trench filling steps. The heterostructure itself provides the reverse-blocking capability as an inherent property.
3Reliability
If peripheral isolation structures are formed through deep trench etching, then reverse-blocking is achieved, but device area and material usage increase
Solution Approach 1:
The patent merges the reverse-blocking diode with the main switching device by forming both structures on the same main surface using the same heteroepitaxial layers. The reverse-blocking diode shares the same substrate and epitaxial structure as the IGBT, eliminating the need for separate peripheral isolation trenches and reducing the overall device footprint.
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 approach reduces the manufacturing complexity, achieves high withstand voltage with low leakage current, and improves reverse recovery characteristics, making it suitable for applications like matrix converters with reduced voltage drop and cost.
Implementation Method 1
a first reverse-blocking heterojunction diode provided on the semiconductor body, configured and arranged to block current reverse to the current switched on/off by the first switching mechanism
Data Source
AI summary
An aspect of the present invention provides a semiconductor device that includes, a first semiconductor body of a first conductivity type, a first switching mechanism provided on the first semiconductor body, configured and arranged to switch on/off current flowing through the semiconductor device, and a first reverse-blocking heterojunction diode provided on the semiconductor body, configured and arranged to block current reverse to the current switched on/off by the first switching mechanism.