Reverse-conducting IGBT Segmented Doping for Leakage and Switching Trade-offs
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Solution Overview
Problem
Existing reverse-conducting IGBTs face challenges in improving device characteristics in one mode without adversely affecting another mode, leading to trade-offs in performance and efficiency.
Innovation Solution
The design incorporates a semiconductor body with specific doping concentrations and structures for IGBT and diode cells, including p-type dopant variations between different regions to optimize performance in both transistor and diode modes, with higher dopant densities in the pilot-IGBT area to reduce leakage current and enhance switching efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the doping concentration in the body region is increased to improve switching efficiency, then switching losses are reduced, but leakage current increases
Solution Approach 1:
The patent applies local quality by implementing different doping concentrations in different regions of the semiconductor device. Specifically, the pilot IGBT area has a higher doping concentration in the body region compared to the main IGBT area, allowing optimized switching performance in the pilot region without compromising the overall leakage current characteristics of the device.
2Loss of energy
If the doping concentration is optimized for IGBT mode to reduce switching losses, then switching efficiency improves, but diode mode performance deteriorates
Solution Approach 1:
The patent segments the semiconductor device into distinct functional areas: a pilot IGBT area with higher doping concentration optimized for switching performance, and a main IGBT area with lower doping concentration optimized for diode mode performance. This segmentation allows each region to be independently optimized for its specific function without adversely affecting the other mode of operation.
3Reliability
If higher dopant densities are used to reduce leakage current, then device characteristics improve at high temperatures, but manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by concentrating the higher doping concentration specifically in the pilot IGBT area rather than uniformly across the entire device. This localized approach reduces leakage current and improves high-temperature characteristics while minimizing the overall manufacturing complexity compared to implementing complex doping structures throughout the entire device.
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 improves the trade-off between device performance and leakage current, particularly at higher operating temperatures, by optimizing dopant distributions and cell structures, resulting in better overall device characteristics and reduced switching losses.
Implementation Method 1
The first IGBT-cell (110) includes a first body region (2) arranged in the semiconductor body (40) and forming a first pn-junction (91) with the drift region (1)
Implementation Method 2
A number of p-type dopants per area in the first IGBT-cell (110) between the first pn-junction (91) and the first surface (15) has a first value
Data Source
AI summary
A reverse-conducting IGBT includes a semiconductor body having a drift region arranged between first and second surfaces. The semiconductor body further includes first collector regions arranged at the second surface and in Ohmic contact with a second electrode, backside emitter regions and in Ohmic contact with the second electrode. In a horizontal direction substantially parallel to the first surface, the first collector regions and backside emitter regions define an rc-IGBT area. The semiconductor body further includes a second collector region of the second conductivity type arranged at the second surface and in Ohmic contact with the second electrode. The second collector region defines in the horizontal direction a pilot-IGBT area. The rc-IGBT area includes first semiconductor regions in Ohmic contact with the first electrode and arranged between the drift region and first electrode. The pilot-IGBT area includes second semiconductor regions of the same conductivity type as the first semiconductor regions.