Galvanic Isolation Barrier Layout for Ultrafast Transient Immunity
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Solution Overview
Problem
Microelectronic devices with high voltage components face challenges in achieving balanced surge protection and IEC-ESD (Electrostatic Discharge) performance, particularly when using silicon nitride layers with higher refractive indices, which degrade transient voltage surge protection and fail to meet IEC-ESD immunity standards.
Innovation Solution
Incorporating a lower-bandgap dielectric layer made of silicon nitride with a refractive index between 2.11 and 2.24, extending beyond the high voltage component and featuring an isolation break, to enhance both surge protection and IEC-ESD performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon nitride layers with higher refractive indices are used in the lower-bandgap dielectric layer, then the bandgap energy is reduced and reliability for the main dielectric is improved, but the transient voltage surge protection is degraded and IEC-ESD immunity standards are not met
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive index of the silicon nitride layer to be within the range of 2.05 to 2.15. This specific parameter range optimizes the bandgap energy reduction for improved dielectric reliability while simultaneously maintaining adequate transient voltage surge protection and IEC-ESD immunity performance
Solution Approach 2:
The patent employs composite materials by creating a lower-bandgap dielectric layer that combines silicon nitride with other dielectric materials. This composite structure achieves the desired bandgap energy characteristics and reliability enhancement while mitigating the harmful effects on surge protection and ESD immunity that would occur with pure high-refractive-index silicon nitride
2Reliability
If the lower-bandgap dielectric layer is made thinner to reduce peak electric fields, then high voltage performance is enhanced, but the surge protection capability is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of the lower-bandgap dielectric layer to be between 10 nm and 100 nm. This specific thickness range is sufficient to reduce peak electric fields at corners of high voltage nodes for enhanced high voltage performance, while being thin enough to maintain adequate surge protection capability
Solution Approach 2:
The patent uses composite materials in the lower-bandgap dielectric layer to achieve the desired electric field reduction with minimal thickness. The combination of materials with different properties allows the layer to provide effective field reduction while maintaining surge protection that would be difficult to achieve with a single material at such thin dimensions
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 significantly improves IEC-ESD breakdown voltage and surge protection capabilities, ensuring reliability and compliance with IEC-ESD standards by reducing electric field peaks and preventing leakage currents.
Implementation Method 1
provides reliability for the main dielectric by reducing peak electric fields at corners of the high voltage node
Implementation Method 2
The sublayer of silicon nitride has a refractive index (RI) between 2.11 and 2.24
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A microelectronic device (100) contains a high voltage component (104) having an upper plate (132) and a lower plate (130). The upper plate is isolated from the lower plate by a main dielectric (136) between the upper plate and low voltage elements (106) at a surface of the substrate (102) of the microelectronic device. A lower-bandgap dielectric layer (140) is disposed between the upper plate and the main dielectric. The lower-bandgap dielectric layer contains at least one sub-layer (144) of silicon nitride having a refractive index between 2.11 and 2.23. The lower-bandgap dielectric layer extends beyond the upper plate continuously around the upper plate. The lower-bandgap dielectric layer has an isolation break (150) surrounding the upper plate at a distance of at least twice the thickness of the lower-bandgap dielectric layer from the upper plate.