Semiconductor Device Lifetime Control for ON Voltage and Qrr Trade-off
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Solution Overview
Problem
The existing semiconductor devices with diode and IGBT regions face challenges in optimizing both ON voltage and reverse recovery charge (Qrr) due to parasitic diode effects, where forming a lifetime controlled region only in the diode region increases ON voltage and forming it in both regions decreases carrier transport efficiency.
Innovation Solution
A semiconductor device with a first lifetime controlled region in the diode region and a second lifetime controlled region in the IGBT region, extending from the boundary between the diode and IGBT regions, positioned to overlap the body region of the IGBT, effectively reducing reverse recovery charge by recombining carriers injected via the parasitic diode without increasing the ON voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lifetime controlled region is formed only in the diode region, then reverse recovery charge is reduced, but ON voltage increases
Solution Approach 1:
The patent applies local quality by forming a lifetime controlled region only in specific areas: the diode region and specifically in the IGBT region at the boundary with the diode region. This localized approach allows carrier recombination to occur where parasitic diode injection happens, reducing reverse recovery charge without introducing lifetime controlled regions across the entire IGBT region that would harm carrier transport efficiency and increase ON voltage.
2Quantity of substance
If a lifetime controlled region is formed in both diode region and IGBT region, then reverse recovery charge is reduced, but carrier transport efficiency decreases and ON voltage increases
Solution Approach 1:
The patent applies local quality by forming a lifetime controlled region only in specific areas: the diode region and specifically in the IGBT region at the boundary with the diode region. This localized approach allows carrier recombination to occur where parasitic diode injection happens, reducing reverse recovery charge without introducing lifetime controlled regions across the entire IGBT region that would harm carrier transport efficiency and increase ON voltage.
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 improves both ON voltage characteristics and reverse recovery charge (Qrr) by effectively reducing carrier injection via the parasitic diode, inhibiting reverse recovery charge increase while maintaining low ON voltage.
Implementation Method 1
The lifetime controlled region is formed to cause excess carriers, which have been injected when the load current was reversely flown, to disappear by recombination so that a reverse recovery charge (Qrr) in a reverse recovery time is reduced.
Implementation Method 2
In the IGBT region, a parasitic diode exists between a body region and a drift region. Consequently, when the load current returns, the parasitic diode is forward biased in the vicinity of the boundary between the diode region and the IGBT region and carriers may be adversely injected via the parasitic diode.
Data Source
AI summary
A diode region and an IGBT region are formed in a semiconductor layer of a semiconductor device. A lifetime controlled region is formed in the semiconductor layer. In a plan view, the lifetime controlled region has a first lifetime controlled region located in the diode region and a second lifetime controlled region located in a part of the IGBT region. The second lifetime controlled region extends from a boundary of the diode region and the IGBT region toward the IGBT region. In the plan view, a tip of the second lifetime controlled region is located in a forming area of the body region in the IGBT region.