Dual Gate Semiconductor Device for IGBT Turn-off Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing insulated gate bipolar transistors (IGBTs) face challenges in reducing turn-off loss and preventing surge voltage during the turn-off operation, which affects power consumption and reliability.
Innovation Solution
The semiconductor device incorporates a dual gate electrode configuration with different threshold voltages for the main and control transistors, where the control transistor is placed on the rear surface, allowing for controlled injection of holes and reducing turn-off loss by preventing hole injection during the turn-off operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gate electrode is provided on the collector electrode side to reduce turn-off loss, then turn-off time is shortened, but surge voltage generation occurs
Solution Approach 1:
The gate electrode is divided into two separate gate electrodes: a first gate electrode on the emitter electrode side and a second gate electrode on the collector electrode side. This segmentation allows independent control of hole injection timing - the first gate electrode controls electron injection while the second gate electrode controls hole injection, enabling turn-off loss reduction without surge voltage generation by coordinating their operation
Solution Approach 2:
The first gate electrode is activated before the second gate electrode during turn-off operation. By preliminarily reducing the gate voltage at the first gate electrode, electrons are extracted from the drift area first, creating a condition where subsequent hole injection control at the second gate electrode can proceed without causing surge voltage
2Loss of energy
If turn-off time is shortened to reduce turn-off loss, then power consumption decreases, but control precision over carrier injection is reduced
Solution Approach 1:
The gate control function is segmented into two independent gate electrodes with different control characteristics. The first gate electrode responds faster to voltage changes for electron control, while the second gate electrode provides sustained control for hole injection management, together achieving both rapid turn-off and precise control
Solution Approach 2:
Different voltage parameters are applied to the two gate electrodes during operation. The first gate electrode uses voltage changes optimized for electron extraction speed, while the second gate electrode uses voltage parameters optimized for hole injection control, allowing each to operate in its optimal parameter range
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 configuration effectively reduces turn-off loss, enhances power efficiency, and prevents surge voltage generation, thereby improving the reliability and performance of the IGBT.
Implementation Method 1
a channel is formed in the p-type base area when a positive voltage higher than a threshold voltage is applied to the gate electrode. Then, electrons are injected from the n-type emitter area into the n-type drift area, and holes are injected from the p-type collector area into the n-type drift area
Data Source
AI summary
A semiconductor device includes a semiconductor layer having first and second surfaces, a first electrode and a first gate electrode along the first surface, and a second electrode and a second gate electrode along the second surface. The layer includes a first type first region, a second type second region between the first region and the first surface and facing the first gate electrode, a first type third region between the second region and the first surface and contacting the first electrode, a second type fourth region between the first region and the second surface, facing the second gate electrode, and contacting the second electrode, and a first type fifth region between the fourth region and the second surface and contacting the second electrode. Transistors including the first and second gate electrodes have different threshold voltages that are both positive or negative.