Semiconductor Buffer Layer Layout for Low-Leakage Soft Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices with high breakdown voltage suffer from increased crystal defects due to proton implantation, leading to reduced minority carrier concentration and increased leakage current, causing high surge voltage and oscillation during switching operations.
Innovation Solution
A semiconductor device with multiple n-type buffer layers formed by proton implantation, where the peak carrier concentration of the closest buffer layer is deeper than 15 μm, and the carrier concentration between buffer layers is calculated to maintain a flat distribution, reducing crystal defects and enhancing carrier storage, thereby suppressing voltage and current oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proton implantation is performed to form n-type buffer layer, then carrier concentration is increased and breakdown voltage is improved, but crystal defects increase leading to increased leakage current
Solution Approach 1:
The patent divides the n-type buffer layer into multiple regions with different carrier concentrations. The buffer layer includes a first region with lower carrier concentration and a second region with higher carrier concentration, allowing the structure to achieve high breakdown voltage while controlling leakage current through the segmented concentration profile
Solution Approach 2:
The patent applies local quality by creating regions with different carrier concentrations within the buffer layer. The first region has lower carrier concentration to reduce leakage current, while the second region has higher carrier concentration to maintain breakdown voltage, with each region optimized for its specific function
2Quantity of substance
If proton implantation is performed to form n-type buffer layer, then carrier storage is enhanced, but crystal defects increase causing voltage and current oscillation during switching
Solution Approach 1:
The patent segments the buffer layer into multiple regions with different carrier concentrations to stabilize switching behavior. The segmented structure prevents excessive carrier storage that would cause oscillation while maintaining sufficient carrier concentration for proper device operation
Solution Approach 2:
The patent changes the carrier concentration parameter spatially within the buffer layer, creating a gradient from lower concentration in the first region to higher concentration in the second region. This parameter variation optimizes both carrier storage and switching stability
3Reliability
If carrier concentration of buffer layer is increased to prevent depletion layer reach-through, then breakdown voltage is improved, but generation loss increases due to increased recombination
Solution Approach 1:
The patent segments the buffer layer into regions with different carrier concentrations to optimize the balance between breakdown voltage and generation loss. The first region with lower concentration reduces recombination losses while the second region with higher concentration ensures adequate depletion layer control
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 solution effectively reduces leakage current and generation loss, ensuring high breakdown voltage and improved soft recovery characteristics while minimizing thermal runaway risks during high-temperature operations.
Implementation Method 1
a method has been known which forms a hydrogen-related donor using the implantation of hydrogen (H) ions (protons)
Implementation Method 2
An activation process for increasing the donor concentration of the VOH defect can be implemented by low-temperature annealing (heat treatment)
Data Source
AI summary
A semiconductor device is disclosed in which proton implantation is performed a plurality of times to form a plurality of n-type buffer layers in an n-type drift layer at different depths from a rear surface of a substrate. The depth of the n-type buffer layer, which is provided at the deepest position from the rear surface of the substrate, from the rear surface of the substrate is more than 15 μm. The temperature of a heat treatment which is performed in order to change a proton into a donor and to recover a crystal defect after the proton implantation is equal to or higher than 400° C. In a carrier concentration distribution of the n-type buffer layer, a width from the peak position of carrier concentration to an anode is more than a width from the peak position to a cathode.