Semiconductor Diode Structure for Reverse Recovery Loss Control
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Solution Overview
Problem
Semiconductor devices with parallel IGBT and FWD configurations face challenges in optimizing loss characteristics and reverse recovery performance due to limitations in adjusting diode resistivities and areas, leading to inefficiencies in current peak suppression and oscillation control.
Innovation Solution
The semiconductor device incorporates first and second diode portions with different resistivities and areas, separated by a high-doping concentration well region, and controlled by lifetime killers, allowing for adjustable resistivity and area ratios to optimize resistivity and area distribution, thereby enhancing reverse recovery performance and reducing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single diode portion is used in parallel with IGBT, then the structure is simple, but the loss characteristics and reverse recovery performance cannot be optimized
Solution Approach 1:
The diode portion is divided into multiple diode portions (first diode portion and second diode portion) with different resistivities and areas. This segmentation allows each diode portion to contribute differently to the reverse recovery process, optimizing loss characteristics while managing the complexity through a systematic multi-component structure.
Solution Approach 2:
Different regions of the diode structure are assigned different resistivities and areas. The first diode portion has different electrical properties than the second diode portion, allowing local optimization of current distribution and reverse recovery behavior to reduce overall energy loss.
2Reliability
If diode resistivity is adjusted to optimize reverse recovery, then reverse recovery performance improves, but manufacturing precision requirements increase
Solution Approach 1:
The diode is segmented into multiple portions with different resistivities, allowing the resistivity control function to be distributed. This segmentation makes it easier to achieve the desired overall reverse recovery performance by optimizing each segment's resistivity independently during manufacturing.
Data Source
AI summary
A semiconductor device is preferably excellent in characteristics such as a loss characteristic. Provided is a semiconductor device including a semiconductor substrate, including an upper-surface electrode provided on an upper surface of the semiconductor substrate; an lower-surface electrode provided on a lower surface of the semiconductor substrate; a transistor portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; a first diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; and a second diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode, wherein the first diode portion and the second diode portion have different resistivities in a depth direction of the semiconductor substrate.