Buried Grid Shield Layout for SiC Voltage Blocking Trade-Off
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Buried grid structures for high voltage wide band gap devices fail to completely block high electric fields, leading to performance limitations due to field peaks at Schottky contacts and thin gate oxides, and there is a need to improve the trade-off between current conducting and voltage blocking characteristics.
Innovation Solution
A buried grid structure with regularly spaced doped wide band gap material parts and spaces, where shields are positioned to cover the middle point between adjacent grid parts, effectively reducing electric field peaks and enhancing shielding, and a method to design this structure by calculating electric fields and positioning shields where they exceed a defined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buried grid structures are used to block high electric fields, then voltage blocking performance is improved, but electric field peaks still occur at Schottky contacts and thin gate oxides limiting device performance
Solution Approach 1:
The shielding function is divided into multiple components: the buried grid structure and additional shields positioned between adjacent grid parts. This segmentation allows each component to address specific electric field regions, with the buried grid providing overall voltage blocking and the intermediate shields specifically targeting field peaks at Schottky contacts and gate oxides.
Solution Approach 2:
The invention adds shields in the lateral dimension between adjacent buried grid parts, rather than only relying on the vertical buried grid structure. This dimensional extension creates a more comprehensive shielding network that blocks electric field peaks in regions that the buried grid alone cannot protect.
2Object-affected harmful factors
If shields are added to cover middle points between adjacent grid parts, then electric field shielding is improved, but device complexity increases
Solution Approach 1:
Shields are strategically positioned only at middle points between adjacent grid parts where electric field peaks occur, rather than providing uniform shielding across the entire device. This localized approach targets specific problematic regions, improving shielding effectiveness while minimizing the addition of structural complexity.
3Object-affected harmful factors
If buried grid spacing is reduced to improve shielding, then electric field blocking is improved, but current conducting capability deteriorates
Solution Approach 1:
The shielding function is segmented between the buried grid structure (which maintains larger spacing for current conduction) and the intermediate shields (which provide additional field blocking). This segmentation allows the buried grid to optimize for current conducting capability while the intermediate shields address electric field blocking, resolving the trade-off between these two functions.
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 achieves a better trade-off between current conducting and voltage blocking characteristics, reducing forward resistance and leakage current while maintaining voltage blocking performance, and allows for higher current density and temperature stability without additional lithographic steps.
Implementation Method 1
Different types of shielding mechanisms, such as surface grid and buried grid as well as trenches are known, proposed, and implemented to protect the sensitive part of high voltage wide band gap devices from the high electric field
Implementation Method 2
the layer comprises a buried grid (2) being a regularly spaced pattern of parts (2) of doped wide band gap material of a first conductivity type (p or n)
Data Source
AI summary
There is disclosed a structure in a wide band gap material such as silicon carbide wherein there is a buried grid and shields covering at least one middle point between two adjacent parts of the buried grid, when viewed from above. Advantages of the invention include easy manufacture without extra lithographic steps compared with standard manufacturing process, an improved trade-off between the current conduction and voltage blocking characteristics of a JBSD comprising the structure.