Deep-Trench Field Ring Termination for Compact High-Voltage Dies
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Solution Overview
Problem
High-voltage semiconductor devices require large high-voltage terminations that occupy a significant portion of the die area, increasing device size and cost, and existing solutions compromise between area usage and blocking voltage or introduce parasitic capacitance and hysteresis issues.
Innovation Solution
A semiconductor device design incorporating a high-voltage termination with a combination of floating field rings and a deep trench filled with dielectric material, which reduces die area usage while maintaining high blocking voltage, suitable for silicon carbide and other semiconductor materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-voltage termination structures are used to ensure high blocking voltage, then blocking voltage is maintained, but die area is significantly increased
Solution Approach 1:
The patent transitions from two-dimensional planar termination structures to three-dimensional vertical structures by forming deep trenches that extend substantially through the epitaxial layer. This vertical dimension allows the termination structure to achieve high blocking voltage capability while occupying less horizontal die area, directly resolving the contradiction between maintaining blocking voltage and reducing die area
Solution Approach 2:
The patent implements nested concentric floating field rings within the termination region, where multiple doped rings are positioned at different radial distances from the center. These nested rings work together to distribute and manage the electric field, enabling compact termination structures that maintain high blocking voltage without requiring excessive die area
2Reliability
If larger termination structures are used to maintain blocking voltage, then blocking voltage is ensured, but parasitic capacitance increases
Solution Approach 1:
By moving the termination function into the vertical dimension through deep trenches, the horizontal footprint is reduced. This dimensional transition decreases the overlap area between conductive regions, thereby reducing parasitic capacitance while maintaining the vertical electric field necessary for high blocking voltage
Solution Approach 2:
The patent extracts the high-voltage termination function from the active device region by implementing dedicated termination structures at the periphery. The deep trenches and floating field rings are positioned to isolate the termination region from the active switching region, separating the high-voltage handling function from the low-voltage active function to minimize parasitic coupling and capacitance
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 achieves a compact high-voltage termination that effectively splits the blocked voltage between floating field rings and the deep trench, reducing die area consumption and parasitic capacitance, thus lowering device costs and improving high-frequency switching performance.
Implementation Method 1
a high-voltage termination including one or more floating field rings and a deep trench disposed around a periphery of an active region of a semiconductor device
Implementation Method 2
reducing die area consumption and parasitic capacitance
Data Source
AI summary
A semiconductor device comprises a substrate, a semiconductor layer formed on the substrate; and a high-voltage termination. The high-voltage termination includes a plurality of floating field rings, a deep trench and a dielectric material is disposed within the deep trench. The plurality of floating field rings are formed in the semiconductor layer and respectively disposed around a region of the semiconductor layer. The deep trench is formed in the semiconductor layer and concentrically disposed around an outermost floating field ring of the plurality of floating field rings. The high-voltage termination may also include a field plate disposed over the floating field rings, the deep trench, or both.