RC IGBT Diode Placement for Thermal and Ohmic Performance
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Solution Overview
Problem
Existing power semiconductor devices, such as RC IGBTs, face challenges in achieving low ohmic connections and low thermal resistance in both forward and reverse conducting states, particularly in the integration of diode structures within the same chip, which affects their performance and efficiency in high voltage and current applications.
Innovation Solution
The proposed solution involves a specific design rule for the placement of diode sections within the active region of the RC IGBT, ensuring that control trenches are interrupted no more than once by a diode section, and that diode sections do not overlap laterally or horizontally, allowing for a low ohmic connection between control electrodes and the control runner structure, while maintaining low thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If diode sections are integrated within the same chip as the IGBT structure, then reverse current capability is provided, but thermal resistance increases and ohmic connection deteriorates
Solution Approach 1:
The active region is divided into multiple diode sections arranged in a specific pattern around the IGBT structure. Each diode section is separated and positioned to optimize thermal pathways, preventing heat accumulation and reducing thermal resistance while maintaining reverse current capability.
Solution Approach 2:
The diode sections are arranged in a lateral distribution around the IGBT structure rather than stacking vertically. This spatial arrangement in the lateral dimension improves heat dissipation pathways and reduces thermal resistance while maintaining electrical connectivity for reverse current flow.
2Adaptability or versatility
If diode sections are integrated within the same chip as the IGBT structure, then reverse current capability is provided, but ohmic connection between control electrodes and control terminal deteriorates
Solution Approach 1:
The control electrode structure is segmented into multiple regions, with control runners extending to each diode section. This segmentation allows independent optimization of control signal pathways, ensuring low ohmic connection and reliable control while maintaining reverse current capability through the integrated diode sections.
3Adaptability or versatility
If control trenches are interrupted by diode sections, then diode properties are achieved, but control electrode continuity is affected
Solution Approach 1:
Control runners act as intermediary structures that extend from the control terminal to each diode section. These runners bridge the gaps created by interrupted control trenches, maintaining electrical continuity and enabling reliable control signal transmission while preserving the diode properties achieved through trench interruption.
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 achieves quasi-gate independent diode properties, reduces turn-on overvoltage, and enhances the overall performance of the RC IGBT by maintaining low ohmic connections and thermal resistance in both conducting states, thereby improving its efficiency in high voltage and current applications.
Implementation Method 1
The control terminal is electrically connected to an electrically conductive control runner structure being arranged at the semiconductor body frontside
Implementation Method 2
Each of the diode sections is configured for conduction of a diode load current between the first load terminal and the second load terminal
Implementation Method 3
The IGBT section is configured for conduction of a forward load current between the second load terminal and the first load terminal
Data Source
AI summary
An RC IGBT includes, in an active region, an IGBT section and at least three diode sections. The arrangement of the diode sections obeys a design rule.