RC-IGBT Re-combination Center for Hole Recombination
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Solution Overview
Problem
In RC-IGBTs, increasing the switching speed of IGBTs leads to anomalies due to excessive positive hole concentration in the p-type well region, which affects the diode's withstand voltage and reverse recovery current.
Innovation Solution
A re-combination center introduction region with higher re-combination center density is provided to reduce positive hole concentration by allowing holes to recombine with electrons, thereby alleviating anomalies and improving diode performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a p-type well region is provided to increase the diode's withstand voltage, then the withstand voltage is improved, but positive holes excessively concentrate in the periphery of the p-type well region during reverse recovery operation, causing anomalies
Solution Approach 1:
The patent introduces a re-combination center in a specific local region (the n-type drift region adjacent to the p-type well region) to create non-uniform carrier recombination characteristics. This localized modification allows the periphery of the p-type well region to have enhanced hole recombination capability without affecting the overall withstand voltage structure, thereby resolving the contradiction between high withstand voltage and reliable switching operation.
2Productivity
If the switching speed of the IGBT is increased, then the productivity and response time are improved, but the concentration of positive holes in the p-type well region increases, causing device anomalies
Solution Approach 1:
The patent preemptively introduces re-combination centers in the n-type drift region before the reverse recovery operation occurs. This preliminary structural arrangement ensures that when high-speed switching causes rapid hole generation and concentration, the re-combination centers are already in place to immediately neutralize excess holes, preventing anomalies even at increased switching speeds.
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
The solution effectively reduces the reverse recovery current and prevents anomalies in the semiconductor device, even at increased switching speeds, by ensuring that holes recombine before reaching the p-type well region, thus enhancing the diode's withstand voltage and recovery resistance.
Implementation Method 1
If a region that has re-combination centers proactively introduced therein is provided, the positive holes re-combine with electrons and disappear, which can relieve the concentration of positive holes
Data Source
AI summary
The re-combination center introduction region has re-combination centers introduced therein so that a density of the re-combination centers in the re-combination center introduction region is higher than a density of re-combination centers in a periphery of the re-combination center introduction region. The re-combination center introduction region continuously extends from the diode region to the peripheral region along a longitudinal direction of the diode region.