Semiconductor Device Platinum Doping Profile
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Solution Overview
Problem
Current methods for producing inhomogeneous platinum distributions in semiconductor substrates are limited, particularly in thermal processes, which can lead to increased switching losses and forward-voltage drop in semiconductor devices like power diodes, due to the uniform distribution of platinum, affecting their performance in high-inductive load applications.
Innovation Solution
A method involving the diffusion of platinum into a semiconductor substrate from one surface, followed by removal of residues and formation of a phosphorus- or boron-doped surface barrier layer for local gettering, creating a vertically inhomogeneous platinum distribution by heating, which adjusts the platinum concentration gradient across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If platinum is uniformly distributed in the semiconductor substrate, then the manufacturing process is simple, but the switching losses and forward-voltage drop increase
Solution Approach 1:
The patent applies local quality by creating a vertically inhomogeneous platinum distribution where the concentration varies with depth in the semiconductor substrate. Specifically, a first concentration is maintained in a first depth region while a second, different concentration is established in a second depth region. This spatial variation in platinum concentration optimizes switching behavior and reduces switching losses in specific regions without requiring complex manufacturing changes overall.
Solution Approach 2:
The patent segments the semiconductor substrate into multiple depth regions with distinct platinum concentrations. The substrate is divided into a first depth region and a second depth region, each with optimized platinum content for their specific functional requirements. This segmentation allows different parts of the device to have tailored electrical characteristics, improving overall device performance.
2Loss of energy
If platinum concentration is increased to reduce switching losses, then switching performance improves, but forward-voltage drop increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially differentiated platinum concentration. In the first depth region, platinum concentration is optimized for reducing switching losses, while in the second depth region, the concentration is adjusted to minimize forward-voltage drop. This localized optimization allows the device to achieve low switching losses without suffering from excessive forward-voltage drop that would result from uniform high platinum concentration throughout the substrate.
3Speed
If heavy metals are introduced to increase recombination rate, then switching speed improves, but leakage current increases
Solution Approach 1:
The patent applies local quality by introducing heavy metals (platinum or gold) at controlled concentrations in specific depth regions rather than uniformly throughout the substrate. In the first depth region, heavy metal concentration is optimized to increase recombination rate and improve switching speed. In the second depth region, the concentration is controlled to minimize the generation of leakage current. This spatial differentiation allows the device to achieve fast switching while maintaining low leakage current characteristics.
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 reduces switching losses and forward-voltage drop by achieving a steep platinum concentration gradient, enhancing the switching behavior and reliability of semiconductor devices in high-voltage applications.
Implementation Method 1
diffusion of platinum or gold into the semiconductor substrate from one of the first and second surfaces
Implementation Method 2
heating the semiconductor substrate for local gettering of the platinum or gold by the phosphorus- or boron-doped surface barrier layer
Implementation Method 3
heating the semiconductor substrate for local gettering of the platinum or gold
Data Source
AI summary
Method of producing a vertically inhomogeneous platinum or gold distribution in a semiconductor substrate with a first and a second surface opposite the first surface, with diffusing platinum or gold into the semiconductor substrate from one of the first and second surfaces of the semiconductor substrate, removing platinum- or gold-comprising residues remaining on the one of the first and second surfaces after diffusing the platinum or gold, forming a phosphorus- or boron-doped surface barrier layer on the first or second surface, and heating the semiconductor substrate for local gettering of the platinum or gold by the phosphorus- or boron-doped surface barrier layer.