Wide Band Gap Buffer Doping Profile for Avalanche Robustness
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Solution Overview
Problem
Wide band gap semiconductor devices face challenges in optimizing avalanche robustness and short circuit withstand capability, requiring design optimization to balance these trade-offs while reducing manufacturing costs.
Innovation Solution
Incorporating a buffer region with a specific vertical doping concentration profile, featuring at least one step and an approximately exponential increase toward the second surface, between the drift region and the highly doped second region, to enhance avalanche robustness and reduce lattice strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If device geometries are shrunk to reduce costs, then manufacturing costs are reduced, but avalanche robustness and short circuit withstand capability deteriorate
Solution Approach 1:
The patent applies local quality by implementing a buffer region with a specific graded doping profile between the drift region and highly doped second region. This localized structural modification with varying doping concentrations (from 1×10^18 to 1×10^20 atoms/cm³) provides enhanced avalanche robustness and short circuit withstand capability in the critical interface region without requiring overall device geometry enlargement, thus resolving the contradiction between cost reduction and reliability improvement
Solution Approach 2:
The patent employs parameter changes by optimizing the doping concentration profile in the buffer region, specifically creating a graded profile that transitions from 1×10^18 to 1×10^20 atoms/cm³. This parameter optimization enables the device to maintain high avalanche robustness and short circuit withstand capability while using shrunk geometries for cost reduction
2Productivity
If device geometries are shrunk to increase device functionalities per unit area, then device functionalities per unit area are increased, but a variety of tradeoffs and challenges arise in design optimization
Solution Approach 1:
The buffer region with graded doping profile provides localized functionality enhancement at the critical drift region-to-highly doped second region interface, enabling high device functionalities per unit area without proportionally increasing overall design complexity
Solution Approach 2:
The buffer region acts as a segmented transition zone between the drift region and highly doped second region, separating the functional requirements and enabling independent optimization of each region while maintaining compact device geometries
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 design improves the reliability and robustness of wide band gap semiconductor devices by suppressing early failures, reducing manufacturing costs, and adapting electric field profiles for specific requirements, while maintaining high current and voltage handling capabilities.
Implementation Method 1
reducing lattice strain
Implementation Method 2
adapting electric field profiles for specific requirements
Data Source
AI summary
A wide band gap semiconductor device includes a semiconductor body having a first surface and a second surface opposite to the first surface along a vertical direction. The semiconductor device further includes a first region of a first conductivity type adjoining at least partially the first surface, a drift region of a second conductivity type, a highly doped second region adjoining the second surface, and a buffer region of the second conductivity type arranged between the drift region and the highly doped second region. A vertical profile of a doping concentration of the buffer region includes at least one step in a first section and is increasing approximately exponentially toward the second surface in a second section. The first section is arranged between the second section and the highly doped second region.