IGBT Trench Junction Structure for SEB-Resistant Electric Field Control
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Solution Overview
Problem
Electric field concentration in semiconductor devices leads to the occurrence of Single Event Burn-out (SEB), and existing technologies struggle to effectively mitigate this issue.
Innovation Solution
A semiconductor device design that includes a semiconductor substrate with an active region, a main junction region, and a termination region, featuring a trench electrode and trench insulating film in the main junction region, connected to the emitter wiring, which helps in reducing electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor device structure is used, then the device can be manufactured with standard processes, but electric field concentration occurs leading to SEB (Single Event Burn-out)
Solution Approach 1:
A trench electrode is introduced as an intermediary element between the collector region and the drift layer. This trench electrode serves as a mediator to redistribute the electric field, preventing concentration at critical junctions. The trench electrode is connected to the collector potential and extends into the drift layer, acting as a field-shaping intermediary that mitigates the harmful electric field concentration without requiring fundamental changes to the semiconductor material structure.
Solution Approach 2:
The invention changes the electric field distribution parameters by introducing a trench structure with specific dimensions and potential. The trench electrode modifies the electric field parameters (field strength, field direction, field distribution pattern) in the drift layer and collector region. By adjusting the trench depth, width, and potential, the electric field parameters are optimized to prevent SEB while maintaining device performance.
2Reliability
If the semiconductor device structure is modified to reduce electric field concentration, then cosmic ray resistance improves, but device complexity increases
Solution Approach 1:
The collector region is segmented by introducing a trench structure that divides the continuous drift layer into regions. The trench electrode creates discrete zones with different electric field characteristics. This segmentation allows independent optimization of different regions - the area under the trench electrode for field control and other areas for current conduction - thereby reducing overall device complexity while improving SEB resistance.
Solution Approach 2:
The invention transitions from a planar two-dimensional structure to a three-dimensional structure by introducing a vertical trench. This dimensional change allows the electric field to be controlled in the vertical direction through the trench depth, providing an additional degree of freedom for field management. The trench electrode extends in the depth direction, enabling three-dimensional electric field shaping that prevents SEB without requiring complex lateral structures.
Data Source
AI summary
According to one embodiment, the semiconductor device 1 includes a semiconductor substrate having an upper surface and a lower surface, and an emitter wiring, wherein when viewed from the upper surface side, the semiconductor substrate has an active region including a plurality of IGBTs, a termination region, and a main junction region, wherein the semiconductor substrate of the main junction region has an N− type drift layer and a P type junction impurity layer, wherein the semiconductor substrate of the termination region has an N− type drift layer and a P type floating layer, wherein at least the main junction region has a trench electrode provided inside the trench, and a trench insulating film provided between the trench electrode and the semiconductor substrate, and wherein the trench electrode and the P type junction impurity layer are connected to the emitter wiring.