SiC Device Barrier Layer for Copper Diffusion Control
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Solution Overview
Problem
Silicon carbide power devices face limitations in achieving high power densities and thermal robustness due to material constraints, particularly in maintaining effective thermal management and preventing diffusion of copper metallization, which affects their performance and reliability.
Innovation Solution
A silicon carbide device structure comprising a nickel-silicon-aluminum contact layer, a titanium-tungsten barrier layer, and a copper metallization layer, where the barrier layer acts as a diffusion barrier to prevent copper diffusion into the substrate, enhancing thermal robustness and allowing for higher power densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper metallization is used to achieve low resistance and high conductivity, then electrical performance is improved, but copper diffusion into the silicon carbide substrate occurs causing device failure
Solution Approach 1:
A multi-layer barrier structure comprising titanium, tungsten, and titanium nitride is introduced as an intermediary between the copper metallization layer and the silicon carbide substrate. This barrier layer structure prevents copper diffusion into the substrate while maintaining electrical conductivity, thereby resolving the contradiction between using copper for low resistance and preventing copper diffusion.
Solution Approach 2:
The barrier layer structure is formed as a composite material system combining titanium, tungsten, and titanium nitride layers. Each material contributes specific properties: titanium provides adhesion and initial barrier, tungsten provides high-temperature stability and diffusion barrier, and titanium nitride provides additional diffusion protection. This composite structure effectively prevents copper diffusion while maintaining device reliability.
2Power
If higher power densities are implemented in silicon carbide devices, then device performance is improved, but thermal management challenges increase
Solution Approach 1:
The invention utilizes the high melting temperature parameter of tungsten (3422°C) and titanium nitride to enable operation at higher power densities. By selecting materials with appropriate thermal parameters, the device can withstand higher temperatures and power densities without compromising thermal robustness, thus resolving the contradiction between increasing power density and maintaining thermal management.
3Ease of manufacture
If the metallization structure is simplified to reduce manufacturing complexity, then ease of manufacture is improved, but diffusion protection and thermal robustness are compromised
Solution Approach 1:
The barrier layer structure combines multiple protective functions into a single integrated layer system. The titanium-w tungsten-titanium nitride composite structure simultaneously provides adhesion, diffusion barrier, and thermal stability functions, achieving reliable diffusion protection without significantly increasing manufacturing complexity. This merged structure resolves the contradiction between simplification and protection requirements.
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 enables silicon carbide devices with improved thermal robustness and higher power densities, reducing capacitance and increasing yield while maintaining a low footprint, and providing better heat dissipation and short-circuit robustness.
Implementation Method 1
a barrier layer structure comprising titanium and tungsten... The barrier layer acts as a diffusion barrier to prevent copper diffusion into the substrate
Data Source
AI summary
A silicon carbide device includes a silicon carbide substrate, a contact layer including nickel, silicon and aluminum, a barrier layer structure including titanium and tungsten, and a metallization layer including copper. The contact layer is located on the silicon carbide substrate. The contact layer is located between the silicon carbide substrate and at least a part of the barrier layer structure. The barrier layer structure is located between the silicon carbide substrate and the metallization layer.