Reverse-Conducting IGBT Trench Layout for Avalanche Breakdown Balance
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Solution Overview
Problem
Conventional reverse-conducting IGBTs face challenges in achieving balanced avalanche breakdown voltages between the transistor and diode portions, leading to uneven current handling and potential semiconductor device breakdown.
Innovation Solution
The semiconductor device design incorporates varying trench intervals and lengths in the diode portion relative to the transistor portion, along with specific doping concentrations and regions, to adjust the avalanche breakdown voltage, ensuring the diode portion breaks down before the transistor portion and preventing semiconductor device breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the transistor portion and diode portion are provided on a single semiconductor substrate, then device integration is achieved, but uneven avalanche breakdown voltage distribution occurs leading to potential device breakdown
Solution Approach 1:
The patent applies local quality by providing different trench structures in the transistor portion and diode portion. The diode portion has trenches with first intervals and first lengths, while the transistor portion has trenches with second intervals and second lengths. This local differentiation allows each region to have optimized avalanche breakdown characteristics suitable for its function, resolving the uneven voltage distribution while maintaining integration.
Solution Approach 2:
The patent employs asymmetry by deliberately designing unequal trench configurations between the diode and transistor portions. The asymmetric trench intervals and lengths create different electric field distributions that compensate for the inherent differences between the two device types, achieving balanced avalanche breakdown voltages across the integrated structure.
2Ease of manufacture
If uniform trench structures are used in both transistor and diode portions, then manufacturing simplicity is maintained, but avalanche breakdown voltage becomes uneven causing current handling imbalance
Solution Approach 1:
Instead of uniform trench structures, the patent implements local quality by specifying different trench parameters for different regions. The diode portion uses trenches with first intervals and first lengths, while the transistor portion uses trenches with second intervals and second lengths. This regional differentiation achieves precise control over avalanche breakdown voltage in each area, improving manufacturing precision without significantly complicating the overall manufacturing process.
3Stability of the object's composition
If the diode portion has the same trench configuration as the transistor portion, then device symmetry is maintained, but the diode portion cannot reach breakdown before the transistor portion preventing device failure
Solution Approach 1:
The patent deliberately breaks symmetry by designing asymmetric trench configurations. The diode portion has trenches with first intervals and first lengths that differ from the second intervals and second lengths in the transistor portion. This asymmetric design ensures that the diode portion reaches avalanche breakdown at a lower voltage than the transistor portion, allowing the diode to act as a protective element that fails first and prevents catastrophic transistor failure.
Solution Approach 2:
The patent applies preliminary anti-action by designing the diode portion's trench structure to intentionally reach breakdown before the transistor portion. This preemptive design ensures that under overvoltage conditions, the diode portion will break down first, creating a protective effect that prevents the transistor portion from experiencing damaging voltage levels, thus preventing device failure.
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 design effectively suppresses avalanche breakdown in the transistor portion by ensuring the diode portion reaches breakdown first, thereby preventing semiconductor device failure and enhancing operational reliability.
Implementation Method 1
adjust the avalanche breakdown voltage, ensuring the diode portion breaks down before the transistor portion and preventing semiconductor device breakdown
Data Source
AI summary
Provided is a semiconductor device including: a semiconductor substrate which has an upper surface and a lower surface and is provided with a drift region of a first conductivity type; a transistor portion which includes a collector region of a second conductivity type in contact with the lower surface of the semiconductor substrate and an emitter region of the first conductivity type provided in contact with the upper surface of the semiconductor substrate and having a doping concentration higher than that of the drift region; and a diode portion which includes a cathode region of the first conductivity type in contact with the lower surface of the semiconductor substrate, and an avalanche breakdown voltage in the diode portion is 0.7 times or more and less than 1 time an avalanche breakdown voltage in the transistor portion.