IGBT Diode Barrier Impurity Segmentation for Recovery Control
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Solution Overview
Problem
The diode recovery characteristics in semiconductor devices with integrated IGBT regions deteriorate when a negative voltage is applied to the gate electrode, leading to excessive hole flow and increased on-resistance.
Innovation Solution
The semiconductor device design includes a diode region with a specific n-type impurity density in the barrier region that contacts the insulating layer, forming a narrower channel compared to the IGBT region, reducing hole flow and maintaining optimal diode recovery characteristics, and also features a thicker insulating layer and higher resistance channel in the diode barrier region to control hole flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the n-type impurity density in the diode barrier region is increased to reduce channel width and hole flow, then diode recovery characteristics improve, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the barrier region into two distinct zones based on n-type impurity density: a first region in contact with the insulating layer with higher density and a second region not in contact with the insulating layer with lower density. This segmentation allows precise control of hole flow at the critical interface while simplifying the overall structure compared to uniformly high doping throughout the entire barrier.
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 prevents excessive hole flow into the diode drift region, improving diode recovery characteristics and reducing on-resistance, thereby enhancing the overall performance of the semiconductor device.
Implementation Method 1
An n-type impurity density of a specific part of the diode barrier region making contact with the second insulating layer is higher than an n-type impurity density of the IGBT barrier region
Implementation Method 2
By applying the negative voltage to the gate electrode, a p-type channel is formed in a range making contact with the insulating layer of the barrier region of the diode region
Implementation Method 3
If the diode region is turned on, holes flow in the following order: a body region at a top side of the barrier region, a channel, a body region at a bottom side of the barrier region, and a drift region
Data Source
AI summary
A semiconductor substrate comprises an IGBT region and a diode region. The IGBT region comprises: an n-type emitter region; a p-type IGBT body region; an n-type IGBT barrier region; an n-type IGBT drift region; a p-type collector region; a first trench; a first insulating layer; and a first gate electrode. The diode region comprises: a p-type diode top body region; an n-type diode barrier region; a p-type diode bottom body region; an n-type cathode region; a second trench; a second insulating layer; and a second gate electrode. An n-type impurity density of a specific part of the diode barrier region making contact with the second insulating layer is higher than an n-type impurity density of the IGBT barrier region.