IGBT Diode Integration on Single Substrate
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Solution Overview
Problem
Inverter circuits for driving inductive motors face challenges in reducing the recovery current of diodes without increasing the forward operation voltage, as existing semiconductor devices with IGBT and diode cell regions formed on separate substrates struggle to achieve both low recovery current and low forward operation voltage simultaneously.
Innovation Solution
A semiconductor device with IGBT and diode cell regions formed on the same substrate, utilizing specific semiconductor regions with controlled impurity concentrations and structural arrangements to reduce recovery current while maintaining a low forward operation voltage, including a trench structure and field stop layers to manage current flow and voltage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the diode is formed on a separate semiconductor substrate from the IGBT, then the device can be manufactured with conventional processes, but the device dimensions increase and integration density decreases
Solution Approach 1:
The patent merges the IGBT cell region and diode cell region onto a single semiconductor substrate, integrating two previously separate devices into one unified structure. This combining approach reduces the overall device dimensions while maintaining the functional independence of both the IGBT and diode through shared substrate infrastructure and common wiring layers.
2Volume of moving object
If the diode and IGBT are formed on the same semiconductor substrate, then the device dimensions are reduced, but the recovery current of the diode increases due to interaction between the cell regions
Solution Approach 1:
The patent segments the semiconductor substrate into distinct IGBT cell regions and diode cell regions, with each region independently configured to optimize its specific function. The IGBT cell region contains emitter, gate, and collector structures, while the diode cell region contains anode and cathode structures. This segmentation allows independent optimization of each device type while maintaining compact integration.
Solution Approach 2:
The patent applies local quality by configuring different semiconductor regions with specific doping types and concentrations tailored to their local functions. The IGBT cell region uses P-type and N-type semiconductor regions arranged for transistor operation, while the diode cell region uses P-type and N-type regions arranged for diode operation. This localized optimization enables both devices to perform their respective functions efficiently within the integrated structure.
3Loss of energy
If the recovery current of the diode is reduced by increasing the forward operation voltage, then the recovery loss decreases, but the forward voltage drop increases and efficiency decreases
Solution Approach 1:
The patent implements preliminary action by configuring the diode cell region with specific P-type and N-type semiconductor region arrangements before operation. The anode region is formed with P-type semiconductor regions and the cathode region with N-type semiconductor regions, creating a structure that inherently limits recovery current without requiring high forward voltages. This pre-configured structure ensures low recovery loss while maintaining efficient forward conduction.
Data Source
AI summary
A semiconductor device includes: a substrate; an active element cell area including IGBT cell region and a diode cell region; a first semiconductor region on a first side of the substrate in the active element cell area; a second semiconductor region on a second side of the substrate in the IGBT cell region; a third semiconductor region on the second side in the diode cell region; a fourth semiconductor region on the first side surrounding the active element cell area; a fifth semiconductor region on the first side surrounding the fourth semiconductor region; and a sixth semiconductor region on the second side below the fourth semiconductor region. The second semiconductor region, the third semiconductor region and the sixth semiconductor region are electrically coupled with each other.