Modular SiC Power Device Layout for Multi-Voltage Fabrication
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Solution Overview
Problem
Current power device manufacturing in SiC requires separate optimization for each voltage class and device type, leading to lengthy development times, limited integration of functions, and increased production costs due to the need for dedicated fabrication processes for each specific area.
Innovation Solution
The design of a power device comprising a high voltage module (HVM) and a low voltage module (LVM), where the HVM features a doped buried grid and epitaxial drift layers, and the LVM includes a feeder contact and low voltage devices, allowing for independent optimization and modular fabrication, reducing the number of necessary fabrication processes and enabling the use of optimized modules across various voltage classes and device types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate optimization is performed for each voltage class and device type, then device performance is optimized, but development time increases and manufacturing complexity increases
Solution Approach 1:
The power device is segmented into a high voltage module (HVM) and a low voltage module (LVM), where the HVM contains the drift layer and buried grid structure optimized for high voltage blocking, and the LVM contains the control structures optimized for low voltage operation. This segmentation allows independent optimization of each module for its specific function while enabling reuse across different voltage classes and device types, thereby reducing overall development time.
2Manufacturing precision
If separate fabrication processes are used for each specific area, then manufacturing precision is improved, but device complexity and production costs increase
Solution Approach 1:
The invention merges the fabrication of high voltage and low voltage structures into a single integrated fabrication process. The HVM and LVM are formed in sequence on the same substrate using a unified process flow that includes common steps such as epitaxial growth, ion implantation, and thermal processing. This merging reduces the number of separate fabrication processes required while maintaining the manufacturing precision needed for each specific structure.
3Manufacturing precision
If dedicated processes are used for each voltage class, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The HVM design with its specific drift layer thickness and doping profile can be reused across multiple voltage classes (e.g., 1200V, 1700V, 3300V) by adjusting only certain parameters such as drift layer thickness. The same basic fabrication process flow and module architecture can produce different voltage class devices, enabling a single production line to manufacture multiple product types without requiring dedicated processes for each voltage class, thereby improving productivity.
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 significantly reduces development time, lowers production costs, and allows for more design flexibility, while providing improved surge current capability and avalanche performance, as the HVM shields the LVM from high electric fields, enabling efficient production of a wide range of power devices with reduced on-resistance.
Implementation Method 1
the HVM shields the LVM from high electric fields
Implementation Method 2
an epitaxial drift layer (3) as a first drift layer with same or opposite conductivity type as the substrate (1), the epitaxial drift layer (3) is applied on the substrate (1)
Data Source
AI summary
A modular concept for Silicon Carbide power devices is disclosed where a low voltage module (LVM) is designed separately from a high voltage module (HVM). The LVM having a repeating structure in at least a first direction, the repeating structure repeats with a regular distance in at least the first direction, the HVM comprising a buried grid (4) with a repeating structure in at least a second direction, the repeating structure repeats with a regular distance in at least the second direction, along any possible defined direction. Advantages include faster easier design and manufacture at a lower cost.