Trench Electrode Semiconductor Layout for Snapback Immunity
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Solution Overview
Problem
Semiconductor devices used in power converters face challenges in maintaining high breakdown immunity under high voltage and high current operations, leading to potential element breakdown and snapback issues.
Innovation Solution
The semiconductor device incorporates a specific electrode and insulating film configuration, including a third electrode within a trench, a control electrode, and a field plate electrode, with controlled electrical resistance and distance settings to manage electric field distribution and prevent avalanche breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor device structure is used, then the device can operate under high voltage and current, but breakdown immunity is insufficient leading to element breakdown and snapback issues
Solution Approach 1:
The device structure is segmented by introducing a trench that divides the semiconductor layer into multiple regions. This segmentation creates distinct functional zones with different electrical characteristics, allowing the high voltage region and low voltage region to be spatially separated, thereby preventing avalanche breakdown while maintaining high voltage current capability
Solution Approach 2:
Different regions of the semiconductor device are assigned different electrical properties through the trench structure. The high voltage region has optimized doping and geometry for withstanding high voltage, while the low voltage region maintains low on-resistance for efficient current conduction. This local differentiation allows each region to perform its function optimally without compromising the other
2Reliability
If the trench depth is increased to improve breakdown voltage, then breakdown immunity improves, but manufacturing precision requirements increase
Solution Approach 1:
Instead of relying solely on increasing trench depth, the invention optimizes other parameters such as trench width, doping concentration in different regions, and the geometric configuration of the semiconductor layers. This multi-parameter optimization achieves high breakdown voltage while maintaining manufacturability with standard precision capabilities
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 enhances breakdown voltage and improves breakover immunity, preventing snapback and element breakdown, thereby increasing the reliability of the semiconductor device under high voltage and current conditions.
Implementation Method 1
The first insulating film electrically insulates the third electrode from the semiconductor part
Implementation Method 2
The third semiconductor layer surrounds the second semiconductor layer on the first semiconductor layer. The third semiconductor layer is apart from the second semiconductor layer
Implementation Method 3
The second semiconductor layer is provided between the first semiconductor layer and the second electrode, and electrically connected to the second electrode. The third semiconductor layer is provided between the first semiconductor layer and the fourth electrode
Data Source
AI summary
A semiconductor device includes a semiconductor part and first to fourth electrodes. The semiconductor part includes a first layer of a first conductivity type and second and third layers of a second conductivity type. The first and second electrodes are provided on back and front surfaces of the semiconductor part, respectively. The third electrode is provided inside a trench of the semiconductor part. The fourth electrode is provided on the front surface of the semiconductor part. The first layer extends between the first electrode and the second and fourth electrodes. The second layer is provided between the first layer and the second electrode. The third layer is provided between the first layer and the fourth electrode. The third electrode includes an end provided between the third layer and the fourth electrode. The third layer is electrically connected to the second electrode via the third and fourth electrodes.