Semiconductor Buffer Region Peak Layout for Depletion Layer Stopping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices with field stop regions fail to effectively stop the depletion layer due to impurity concentration peaks that sequentially decrease from the back surface, leading to suboptimal device characteristics and breakdown voltage.
Innovation Solution
A semiconductor device with a buffer region having multiple doping concentration peaks, including a high-concentration peak closer to the upper surface and a low-concentration peak closer to the back surface, where the doping concentration ratio between the peaks is controlled to optimize the field stop function and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impurity concentration peaks sequentially fall from the back surface side in the conventional field stop region, then the manufacturing process is simple, but the field stop function is insufficient and breakdown voltage is reduced
Solution Approach 1:
The patent applies parameter changes by inverting the doping concentration distribution pattern. Instead of sequential decrease from back surface, the invention uses a pattern where the peak closest to back surface has lower concentration than peaks closer to upper surface. This parameter inversion resolves the contradiction by achieving effective field stop function (improving breakdown voltage) while maintaining manufacturing feasibility through controlled doping processes.
Solution Approach 2:
The patent applies local quality by creating non-uniform doping concentration peaks at specific depths within the buffer region. Each peak is positioned at a specific depth range (1-12 μm from back surface) with optimized concentration ratios (N2/N1 ≤ 100), providing localized high-field regions that effectively stop depletion layer extension while maintaining overall device performance.
2Reliability
If multiple doping concentration peaks are introduced in the buffer region, then the field stop function is enhanced, but the manufacturing precision requirement increases
Solution Approach 1:
The patent defines specific parameter ranges to balance field stop function and manufacturing precision. The doping concentration ratio N2/N1 is controlled to be ≤ 100, and peaks are positioned at specific depth ranges (1-12 μm from back surface). These parameter specifications provide clear manufacturing targets while achieving effective depletion layer stopping, resolving the contradiction between enhanced function and precision requirements.
3Reliability
If the first peak is positioned closer to the back surface with lower concentration, then the depletion layer stopping is optimized, but the doping concentration distribution becomes more complex
Solution Approach 1:
The patent applies inversion by reversing the conventional doping concentration pattern. Instead of highest concentration at back surface, the first peak (closest to back surface) has lower concentration than subsequent peaks. This inverted pattern optimizes depletion layer stopping by creating appropriate field distribution while the concentration ratios (N2/N1 ≤ 100) keep the complexity manageable through defined relationships between peaks.
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 optimized doping concentration distribution enhances the breakdown voltage and manufacturing efficiency by effectively suppressing the depletion layer extension and reducing leakage current, while maintaining the function of the field stop layer.
Implementation Method 1
a buffer region of the first conductivity type provided in the drift layer, the buffer region having a plurality of peaks of a doping concentration
Implementation Method 2
a high-concentration peak which has a higher doping concentration than the first peak, and is provided closer to an upper surface of the semiconductor substrate than the first peak is
Data Source
AI summary
Provided is a semiconductor device including a buffer region. Provided is a semiconductor device including: semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type provided in the semiconductor substrate; and a buffer region of the first conductivity type provided in the drift layer, the buffer region having a plurality of peaks of a doping concentration, wherein the buffer region has: a first peak which has a predetermined doping concentration, and is provided the closest to a back surface of the semiconductor substrate among the plurality of peaks; and a high-concentration peak which has a higher doping concentration than the first peak, and is provided closer to an upper surface of the semiconductor substrate than the first peak is.