SiC Semiconductor Edge Termination with Source Ring for Breakdown
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional silicon carbide semiconductor devices face issues with high ON resistance due to the narrow edge termination region, leading to increased displacement current and potential element destruction during voltage switching, as the reduction in edge termination width and thickness compromises breakdown voltage and current handling capabilities.
Innovation Solution
The semiconductor device incorporates a source ring region surrounding the gate ring region, with a second source electrode and a p-type base layer to extract hole current from the edge termination region, mitigating current concentration and enhancing breakdown tolerance by facilitating the extraction of displacement current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the edge termination region width and thickness are reduced to lower ON resistance, then ON resistance decreases, but breakdown voltage capability deteriorates and displacement current increases causing potential element destruction
Solution Approach 1:
The device is divided into distinct functional regions: an active region with reduced ON resistance and a termination region with enhanced breakdown voltage capability. The termination region is further segmented into multiple layers (first termination layer, second termination layer, third termination layer) with different impurity concentrations and structures, allowing each segment to address specific aspects of the breakdown voltage problem while the active region maintains low ON resistance.
Solution Approach 2:
Different regions of the semiconductor device are given different local properties: the active region has low impurity concentration for low ON resistance, while the termination region has high impurity concentration and specific structural features (protrusions, recesses, multiple layers) for high breakdown voltage capability. This local differentiation allows simultaneous optimization of both ON resistance and breakdown voltage.
Solution Approach 3:
The termination region structure extends in multiple dimensions: vertically with multiple layers at different depths (first, second, and third termination layers at different positions from the front surface), and horizontally with protrusions and recesses creating a three-dimensional structure. This multi-dimensional approach allows the termination region to handle displacement current and maintain breakdown voltage capability without increasing the planar width excessively.
2Productivity
If the edge termination region is narrowed to improve current density, then current handling improves, but current concentration increases leading to higher displacement current and element destruction risk
Solution Approach 1:
The harmful displacement current generated in the termination region is converted into a beneficial effect by providing a dedicated current path. The first termination layer with high impurity concentration and the conductive type opposite to the second semiconductor layer creates a pn junction that efficiently channels displacement current away from the active region, transforming the harmful current concentration into a controlled current flow that protects the active region.
Solution Approach 2:
The termination region structures (first termination layer, second termination layer, third termination layer) act as intermediary elements between the active region and the external environment. These intermediate layers with specific impurity concentrations and structures mediate the displacement current, preventing it from directly affecting the active region while maintaining the narrow edge termination geometry needed for high current density.
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 current concentration at the active region, improves breakdown tolerance, and prevents element destruction by efficiently extracting hole current, thereby enhancing the performance and reliability of silicon carbide semiconductor devices.
Implementation Method 1
a second source electrode and a p-type base layer to extract hole current from the edge termination region, mitigating current concentration and enhancing breakdown tolerance by facilitating the extraction of displacement current
Data Source
AI summary
A semiconductor device includes an active region, a gate ring region surrounding a periphery of the active region, and a source ring region surrounding a periphery of the gate ring region. The semiconductor device has a semiconductor substrate of a first conductivity type, a first semiconductor layer of the first conductivity type, a second semiconductor layer of a second conductivity type, and a second electrode. The semiconductor device has, in the active region, first semiconductor regions of the first conductivity type, a gate insulating film, first gate electrodes, an interlayer insulating film and a first first-electrode, and has, in the source ring region, a third semiconductor region and a second first-electrode. In the source ring region, a second semiconductor region of the first or second conductivity type is provided at a bottom of the third semiconductor region, directly below the second first-electrode in a depth direction of the semiconductor device.