Compensated Silicon Wafer Doping for Breakdown Control
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Solution Overview
Problem
Silicon semiconductor devices face challenges in achieving high electrical breakdown voltage and low on-state resistance while minimizing avalanche breakdown events and undesired inversion channel formation, particularly due to segregation effects during the Czochralski method of silicon wafer growth.
Innovation Solution
A silicon wafer with a net n-type doping concentration of 1×10^13 cm^-3 to 1×10^15 cm^-3, partially compensated by 10% to 80% with p-type dopants, including a portion of 5% to 75% hydrogen-related donors, is manufactured by adding p-type dopants to the silicon melt during ingot extraction and forming hydrogen-related donors through proton irradiation and annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the Czochralski method is used to grow silicon wafers with defined doping, then silicon semiconductor devices can be manufactured, but segregation effects cause doping concentration to increase with distance from the seed crystal, making it difficult to achieve uniform doping
Solution Approach 1:
p-type dopants are added to the silicon melt during the extraction process to compensate for the n-type doping segregation effect before it completes, counteracting the concentration increase that would otherwise occur with distance from the seed crystal
Solution Approach 2:
The doping approach changes from using only n-type dopants to using a combination of n-type and p-type dopants, fundamentally altering the doping parameter strategy to achieve uniform net n-type doping concentration throughout the ingot
2Reliability
If high electrical breakdown voltage is achieved through doping, then device performance improves, but avalanche breakdown events and undesired inversion channel formation occur, reducing device robustness and reliability
Solution Approach 1:
Hydrogen-related donors are introduced to create localized compensation effects at critical interfaces and regions where avalanche breakdown and inversion channel formation are most likely to occur, providing targeted protection while maintaining overall device performance
Solution Approach 2:
The doping structure becomes composite by combining n-type dopants, p-type dopants, and hydrogen-related donors, creating a multi-component doping system that achieves both high breakdown voltage and enhanced reliability through the synergistic effects of different dopant types
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 enhances the robustness and reliability of silicon semiconductor devices by reducing carrier mobility, minimizing avalanche breakdown, and reducing variations in specific resistance, thereby improving the yield of wafers with target resistance values.
Implementation Method 1
Molten silicon freezes on the silicon seed crystal
Implementation Method 2
forming hydrogen related donors in the silicon wafer by irradiating the silicon wafer with protons
Implementation Method 3
annealing the silicon wafer
Data Source
AI summary
A method of manufacturing is provided that includes providing an n-type silicon wafer, the n-type silicon wafer including n-type dopants partially compensated 20% to 80% by p-type dopants, where a net n-type doping concentration of the n-type silicon wafer is in a range from 1×1013 cm−3 to 1×1015 cm−3; forming hydrogen related donors in the n-type silicon wafer by irradiating the n-type silicon wafer with protons; and annealing the n-type silicon wafer after forming the hydrogen related donors.