Semiconductor Seed Layer Via Field Redistribution
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Solution Overview
Problem
GaN-based semiconductor devices face challenges in high-voltage operation due to negative charge accumulation in epitaxial layers, which existing grounding methods cannot address for all substrate types, especially in demanding high-frequency and high-temperature environments.
Innovation Solution
A semiconductor structure with a pair of through-substrate vias that contact a seed layer, generating a voltage difference inside the seed layer to extend the electric field line to an insulating layer, thereby redistributing the electric field and increasing the breakdown voltage, allowing for high-voltage operation without shielding the high electric field region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high electron mobility transistor (HEMT) device operates at high voltage, then the device can achieve higher power output, but negative charges in the epitaxial layer are attracted to upper components, adversely affecting device operation
Solution Approach 1:
The patent introduces a seed layer as an intermediary component between the substrate and the compound semiconductor layer. This seed layer serves as a mediator to manage charge distribution and prevent negative charges from migrating to upper components during high-voltage operation, thus maintaining device reliability while enabling high power output.
Solution Approach 2:
The patent extracts the charge management function from the traditional substrate grounding approach and relocates it to the seed layer. By taking out the charge accumulation problem from the epitaxial layer and addressing it at the seed layer level, the solution prevents charge migration to upper components while maintaining high-voltage operation capability.
2Reliability
If traditional grounding methods are used to discharge negative charges, then charge accumulation is reduced, but this method is not feasible for all types of substrates
Solution Approach 1:
The patent creates a universal charge management solution by implementing the seed layer structure that can be applied across different substrate types. The seed layer serves multiple functions: it acts as a charge management layer, a structural interface, and a compatible foundation for various substrate materials including silicon, silicon carbide, and sapphire, making the solution universally applicable.
Solution Approach 2:
The patent changes the structural parameters of the semiconductor device by introducing the seed layer with specific material properties and thickness parameters. This parameter change enables effective charge discharge functionality that is independent of substrate type, allowing the same structural approach to work across different substrate materials.
3Reliability
If the seed layer is used to manage charges, then charge distribution is improved, but the structure becomes more complex
Solution Approach 1:
The patent merges the charge management function with the existing seed layer structure that is already necessary for epitaxial growth. By combining charge management responsibilities with the seed layer's inherent structural role, the solution avoids adding separate complex charge management components, thus improving charge distribution while minimizing structural complexity.
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 semiconductor structure effectively increases the breakdown voltage and enhances performance under high-voltage conditions by redistributing the electric field, enabling reliable operation in demanding environments.
Implementation Method 1
the pair of through-substrate vias pass through the isolation structure and contact the seed layer... the source structure and the drain structure are respectively electrically connected to the seed layer by the pair of through-substrate vias
Implementation Method 2
generating a voltage difference inside the seed layer so that the electric field line extends to the layer (e.g., an insulating layer) disposed under the seed layer
Data Source
AI summary
A semiconductor structure includes a substrate having an active region and an isolation region, an insulating layer disposed on the substrate, a seed layer disposed on the insulating layer, a compound semiconductor layer disposed on the seed layer, a gate structure in the active region disposed on the compound semiconductor layer, an isolation structure in the isolation region disposed on the substrate, a pair of through-substrate vias in the isolation region disposed on the opposite sides of the gate structure, and a source structure and a drain structure disposed on the substrate and on the opposite sides of the gate structure. The pair of through-substrate vias pass through the isolation structure and contact the seed layer. The source structure and the drain structure electrically connect the seed layer by the pair of through-substrate vias.