Unipolar Semiconductor Component for Power Module Service Life
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Solution Overview
Problem
The service life of power modules with unipolar semiconductor components is limited by the temperature rise from part load to full load operation, as existing designs exhibit a linear increase in resistance with temperature, leading to excessive heating and reduced reliability.
Innovation Solution
A custom-designed unipolar semiconductor component with a temperature-dependent resistance profile, featuring high resistance at low temperatures that decreases with self-heating, resulting in a significant reduction in temperature rise between part load and full load, achieved by configuring the ionisation energy of dopants in the drift region, such as using dopants with high ionisation energies like phosphorus in 4H-SiC or boron in diamond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional unipolar semiconductor components with linear resistance increase are used, then the device structure is simple and manufacturing is easy, but the temperature rise from part load to full load is excessive, reducing service life
Solution Approach 1:
The patent changes the electrical parameter (resistance) of the semiconductor component by selecting dopants with specific ionisation energies. The drift region is doped with dopants having high ionisation energy (250-500 meV) to create a non-linear resistance-temperature characteristic, where resistance decreases as temperature increases from part load to full load operation, thereby reducing temperature rise and extending service life.
2Reliability
If dopants with high ionisation energy are used in the drift region, then temperature rise is reduced and service life is extended, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by doping only the drift region with specific high ionisation energy dopants, while other regions of the semiconductor component may have different doping characteristics. This localized approach allows precise control of the resistance-temperature relationship in the critical drift region without requiring uniform high precision doping throughout the entire component, thereby managing manufacturing complexity.
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 design extends the service life of the semiconductor component and power module by minimizing temperature rise between part load and full load, allowing for either increased reliability or reduced chip area with comparable service life, thereby saving space and costs.
Implementation Method 1
A temperature rise of the semiconductor component, from a first temperature up to which the semiconductor component heats during operation at 50 % of full load, to a second temperature up to which the semiconductor component heats during operation at full load
Data Source
AI summary
In a power module that has a carrier substrate with at least one unipolar semiconductor component as a power switch, the unipolar semiconductor component is configured such that a temperature rise of the semiconductor component, from a first temperature up to which the semiconductor component heats in operation at 50% full load, to a second temperature up to which the semiconductor component heats in operation at full load, is less than a temperature rise of the semiconductor component from an initial temperature at zero load to the first temperature. As a result of the reduced temperature rise between 50% and 100% full load the service life of the power module can be lengthened.