Wide Bandgap Semiconductor Device With Segmented Impurity Regions
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Solution Overview
Problem
Wide bandgap semiconductor devices with Schottky electrodes face challenges in achieving high breakdown voltage while minimizing electric resistance, as increasing breakdown voltage often results in increased electric resistance and vice versa.
Innovation Solution
A wide bandgap semiconductor device structure is implemented, featuring a Schottky electrode in contact with a wide bandgap semiconductor layer that includes a first impurity region and a second impurity region, where the second region is divided into a first region in contact with the Schottky electrode and a second region connected to the first region, with the maximum width of the second region being larger than the boundary portion between the first region and the Schottky electrode, thereby optimizing breakdown voltage and reducing electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a Schottky barrier diode structure with multiple junction barriers is used to achieve high breakdown voltage, then breakdown voltage is improved, but electric resistance increases
Solution Approach 1:
The second impurity region is divided into a first region in contact with the Schottky electrode and a second region connected to the first region, with the maximum width of the second region being larger than the boundary portion between the first region and the Schottky electrode. This segmentation allows the depletion layer to extend effectively into the second region, improving breakdown voltage while the first region maintains lower contact resistance at the electrode interface.
Solution Approach 2:
The patent applies different impurity concentrations and regional configurations to different parts of the semiconductor layer. The first impurity region has higher impurity concentration for low contact resistance, while the second impurity region has lower impurity concentration for high breakdown voltage. This local quality differentiation resolves the contradiction between low resistance and high breakdown voltage.
2Object-affected harmful factors
If the width of the second impurity region is increased to reduce electric resistance, then contact resistance is improved, but breakdown voltage decreases
Solution Approach 1:
By segmenting the second impurity region into first and second regions with different width profiles, the patent achieves both low contact resistance (through the first region's wider boundary contact) and high breakdown voltage (through the second region's extended depletion layer formation).
Solution Approach 2:
The patent utilizes the depth dimension by having the second region extend closer to the second main surface, creating a three-dimensional impurity distribution that optimizes both surface contact properties and bulk breakdown characteristics simultaneously.
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 allows for a high breakdown voltage with low electric resistance, suppressing increases in voltage drop and forward voltage, while effectively reducing leak current and contact resistance.
Implementation Method 1
A Schottky barrier diode is a diode which applies a Schottky barrier formed by a junction between a metal and a semiconductor
Implementation Method 2
the p-type region is arranged to suppress a reverse current which flows through the n-type region, the metal layer, and a pn junction formed by the n-type region and the p-type region when a reverse voltage is applied to the junction, using a space-charge region formed in then-type region
Data Source
AI summary
A wide bandgap semiconductor device includes a wide bandgap semiconductor layer and a Schottky electrode. The wide bandgap semiconductor layer includes a first impurity region which is in contact with the Schottky electrode, is in contact with a second main surface, and has a first conductivity type, and a second impurity region which is in contact with the Schottky electrode, is in contact with the first impurity region, and has a second conductivity type. The second impurity region has a first region which is in contact with the Schottky electrode, and a second region which is connected with the first region and provided on a side of the first region closer to the second main surface. A maximum value of a width of the second region is larger than a width of a boundary portion between the first region and the Schottky electrode.