Semiconductor Diode Junction Termination Extension for Reverse Breakdown Voltage
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Solution Overview
Problem
Conventional diodes have a reverse breakdown voltage threshold that can lead to malfunction and hazardous conditions when voltage is applied in the opposite direction, as they can conduct current opposite to the intended direction beyond this threshold.
Innovation Solution
A semiconductor diode structure with a junction termination extension (JTE) formed via ion implantation, which spreads the electric field and increases the reverse breakdown voltage by creating a bilayer with a non-conductive surface layer and a low hole concentration layer, thereby preventing unintended current conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional diode structure is used, then the device is simple and easy to manufacture, but the reverse breakdown voltage is limited and the device may malfunction under high reverse voltage
Solution Approach 1:
The diode structure is segmented into multiple functional layers: a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer with junction termination extensions. This segmentation allows each layer to perform specific functions, with the third layer specifically designed to extend the electric field and increase reverse breakdown voltage beyond conventional single-layer structures.
Solution Approach 2:
The third semiconductor layer introduces local quality variations through junction termination extensions that create non-uniform doping concentrations. These extensions have different hole concentrations compared to the bulk material, creating localized regions that modify the electric field distribution specifically at the edges where breakdown typically occurs, thereby increasing overall reverse breakdown voltage.
2Reliability
If the reverse breakdown voltage is increased through structural modifications, then the reliability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The junction termination extensions are formed during the epitaxial growth process itself, rather than requiring subsequent separate fabrication steps. The third semiconductor layer is grown with predetermined doping concentrations that create the desired extension structures, integrating the complexity into the standard growth process and avoiding additional manufacturing steps.
Solution Approach 2:
The invention achieves increased reverse breakdown voltage by changing the doping parameters during epitaxial growth. By controlling the hole concentration in the third semiconductor layer and creating graded doping profiles, the electric field distribution is optimized without requiring complex post-growth processing or additional material deposition steps.
3Reliability
If a junction termination extension is added to spread the electric field, then the reverse breakdown voltage increases, but the device structure becomes more complex
Solution Approach 1:
The junction termination extensions are merged with the third semiconductor layer as a single integrated structure grown in one epitaxial process. Rather than adding separate components or layers, the extensions are formed as part of the continuous semiconductor layer with spatially varying doping concentrations, combining the termination function with the bulk layer structure.
Solution Approach 2:
The third semiconductor layer functions as a composite structure with regions of different doping concentrations within the same material layer. The junction termination extensions create a composite doping profile where high-hole-concentration regions are embedded within the lower-hole-concentration third layer, achieving electric field control through internal material composition variation rather than additional structural elements.
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 diode structure effectively increases the reverse breakdown voltage, preventing malfunction and hazardous conditions by spreading the electric field over a larger surface area, allowing for safer operation under higher reverse voltages.
Implementation Method 1
a junction termination extension (JTE) formed via ion implantation
Data Source
AI summary
A diode includes a second semiconductor layer over a first semiconductor layer. The diode further includes a third semiconductor layer over the second semiconductor layer, where the third semiconductor layer includes a first semiconductor element over the second semiconductor layer. The third semiconductor layer additionally includes a second semiconductor element over the second semiconductor layer, wherein the second semiconductor element surrounds the first semiconductor element. Further, the third semiconductor layer includes a third semiconductor element over the second semiconductor element. Furthermore, a hole concentration of the second semiconductor element is less than a hole concentration of the first semiconductor element.