SiC Power Device Passivation Anchoring Against Thermal Delamination
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Solution Overview
Problem
Silicon carbide power devices face reliability issues due to delamination of passivation layers caused by thermomechanical stresses during thermal cycles, leading to electrical arching phenomena and device damage.
Innovation Solution
A manufacturing process for silicon carbide power devices that includes forming an anchorage region within an anchorage opening in the dielectric layer, which provides mechanical anchorage for the passivation layer, preventing delamination during thermal cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyimide passivation layer is deposited on the silicon carbide substrate using spin-coating, then the device achieves insulation function, but the passivation layer delaminates after thermal cycles due to thermomechanical stresses
Solution Approach 1:
The patent applies preliminary action by forming recesses in the dielectric layer before depositing the passivation layer. These pre-formed recesses create mechanical interlocking features that prevent delamination during subsequent thermal cycles, addressing the adhesion problem before it occurs.
Solution Approach 2:
The patent applies local quality by creating localized recesses only in specific areas where the passivation layer needs enhanced anchorage. This targeted approach improves adhesion at critical stress points without modifying the entire device structure, maintaining insulation properties while preventing delamination.
2Strength
If the passivation layer is made thin to reduce stress, then thermomechanical stress is reduced, but electrical breakdown occurs more easily
Solution Approach 1:
The patent transitions from a two-dimensional planar structure to a three-dimensional structure by forming recesses that extend vertically into the dielectric layer. This dimensional change allows the passivation layer to be anchored mechanically at multiple depths, providing stress resistance without compromising electrical insulation thickness.
Solution Approach 2:
The patent creates a composite structure combining the dielectric layer with recesses and the passivation layer. This composite design integrates mechanical anchorage features with electrical insulation, achieving both stress resistance and high breakdown voltage through the synergistic combination of structural elements.
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 enhances the robustness and reliability of silicon carbide power devices by preventing passivation layer delamination and subsequent electrical arching, thereby ensuring stable operation under thermal stress.
Implementation Method 1
forming an anchorage region within an anchorage opening in the dielectric layer, wherein the passivation layer provides the mechanical anchorage
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 1G~2
AI summary
An electronic power device (25) is provided with: a substrate (2) of silicon carbide (SiC), having a front surface (2a) and a rear surface (2b), which lie in a horizontal plane (xy) and are opposite to one another along a vertical axis (z), the substrate including an active area (A'), provided in which are a number of doped regions (4), and an edge area (A"), which is not active, distinct from and surrounding the active area (A'); a dielectric region (8a) arranged above the front surface (2a), at least at the edge area (A"); and a passivation layer (20) arranged above the front surface (2a) of the substrate (2), in contact with the dielectric region (8a) in the edge area (A"). The passivation layer (20) comprises at least one anchorage region (22) that extends throughout the thickness of the dielectric region (8a) at the edge area (A"), such as to define a mechanical anchorage for the passivation layer (20).