Power Semiconductor Pillars for Super Junctions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional IGBTs face a trade-off between on-state resistance and breakdown voltage due to the limitations of doping concentration, and the complex, time-consuming process of forming deep P-type doping regions using super junction techniques increases production costs.
Innovation Solution
The method involves forming a power semiconductor device with a substrate having trenches and semiconductor pillars that create super junctions, reducing on-state voltage and increasing breakdown voltage through a simpler and more efficient process compared to traditional epitaxial growth and ion implantation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the doping concentration of the substrate is increased to lower the on-state voltage, then the on-state voltage is reduced, but the breakdown voltage will be reduced
Solution Approach 1:
The substrate is segmented into multiple regions with different doping concentrations: a first doped region with higher doping concentration near the surface to reduce on-state voltage, and a second doped region with lower doping concentration deeper in the substrate to maintain breakdown voltage. This spatial segmentation allows both contradictory requirements to be satisfied simultaneously in different locations.
Solution Approach 2:
Different regions of the substrate are assigned different doping concentrations according to their functional requirements. The first doped region has higher doping concentration locally to reduce resistance and on-state voltage, while the second doped region has lower doping concentration locally to sustain high breakdown voltage, achieving local optimization of electrical properties.
2Reliability
If conventional super junction techniques are used to break the restriction between on-state resistance and breakdown voltage, then the breakdown voltage is increased, but the process becomes complex and time-consuming
Solution Approach 1:
The formation of the first and second doped regions is merged into a single ion implantation process step, combining what would traditionally require separate epitaxial growth and doping steps into one operation, thereby simplifying the fabrication process while achieving the desired dual-doped structure.
Solution Approach 2:
The ion implantation process uses different implantation conditions (energy, dose, angle) to create two distinct doped regions with different doping concentrations in a single step, changing the process parameters dynamically during the same operation to achieve what would otherwise require multiple process steps.
3Reliability
If the doping concentration of the substrate is decreased to increase the breakdown voltage, then the breakdown voltage is increased, but the on-state resistance is increased and the on-state voltage is relatively high
Solution Approach 1:
The substrate is segmented into multiple regions with different doping concentrations: a first doped region with higher doping concentration near the surface to reduce on-state voltage, and a second doped region with lower doping concentration deeper in the substrate to maintain breakdown voltage. This spatial segmentation allows both contradictory requirements to be satisfied simultaneously in different locations.
Solution Approach 2:
Different regions of the substrate are assigned different doping concentrations according to their functional requirements. The first doped region has higher doping concentration locally to reduce resistance and on-state voltage, while the second doped region has lower doping concentration locally to sustain high breakdown voltage, achieving local optimization of electrical properties.
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 approach allows for a significant reduction in on-state voltage and an increase in breakdown voltage while simplifying the fabrication process, reducing production time and costs, and enabling rapid turn-off capabilities.
Implementation Method 1
the semiconductor pillars and the substrate form a plurality of super junctions of the power semiconductor device for increasing the breakdown voltage of the power semiconductor device and reducing the on-state voltage of the power semiconductor device
Data Source
AI summary
A method for forming a power semiconductor device is provided. The method includes providing a substrate having a first surface and a second surface; and forming a plurality of trenches in the second surface of the substrate. The method also includes forming a semiconductor pillar in each of the plurality of trenches, wherein the semiconductor pillars and the substrate form a plurality of super junctions of the power semiconductor device for increasing the breakdown voltage of the power semiconductor device and reducing the on-stage voltage of the power semiconductor device; and forming a gate structure on the first surface of the substrate. Further, the method includes forming a plurality of well regions in the first surface of the substrate around the gate structure; and forming a source region in each of the plurality of well regions around the gate structure.