Vertical Semiconductor Device Radiation Tolerance Step Doping
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Solution Overview
Problem
Conventional vertical semiconductor devices for high power applications are prone to failure due to radiation intolerance, leading to catastrophic breakdowns when exposed to high voltages and radiation particles.
Innovation Solution
The implementation of a vertical semiconductor device structure comprising a substrate, a buffer layer with a lower doping concentration than the substrate, and a drift layer with an even lower doping concentration, creating a step doping profile that enhances radiation tolerance and ruggedness by allowing charge particle recombination rather than passage through the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a conventional vertical semiconductor device structure is used with heavily doped substrate and drift layer, then high blocking voltage is achieved, but radiation tolerance deteriorates leading to catastrophic failure
Solution Approach 1:
The drift layer is divided into multiple regions with different doping concentrations (first drift layer region with higher doping, second drift layer region with lower doping). This segmentation allows the device to maintain high blocking voltage through the heavily doped first region while the lightly doped second region provides radiation tolerance by reducing charge particle passage and minimizing radiation-induced damage propagation.
Solution Approach 2:
Different regions of the drift layer are assigned different doping concentrations tailored to their specific functional requirements. The first drift layer region near the junction uses higher doping for voltage blocking, while the second drift layer region uses lower doping for radiation hardness. This local quality differentiation resolves the contradiction between high voltage capability and radiation tolerance.
2Stress or pressure
If doping concentration is increased to improve blocking voltage, then voltage handling capability is improved, but radiation intolerance increases causing device failure
Solution Approach 1:
The drift layer is segmented into two regions with different doping concentrations. The first drift layer region maintains higher doping for voltage handling, while the second drift layer region uses lower doping to reduce radiation intolerance. This segmentation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
The doping concentration parameter is changed across different regions of the drift layer. By varying the doping concentration from higher in the first region to lower in the second region, the device achieves both high voltage handling capability and reduced radiation intolerance, resolving the contradiction between these two parameters.
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 significantly increases the second breakdown voltage and radiation tolerance, reducing the failure rate and enhancing the device's ruggedness, thereby preventing catastrophic failures under high voltage and radiation conditions.
Implementation Method 1
creating a step doping profile that enhances radiation tolerance and ruggedness by allowing charge particle recombination rather than passage through the device
Data Source
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AI summary
A vertical semiconductor device includes a substrate, a buffer layer over the substrate, and a drift layer over the buffer layer. The substrate has a first doping type and a first doping concentration. The buffer layer has the first doping type and a second doping concentration that is less than the first doping concentration. The drift layer has the first doping type and a third doping concentration that is less than the second doping concentration.