Silicon Carbide Back-Metal Stack to Prevent Silicide Delamination

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Solution Overview

Problem

Silicon carbide devices suffer from mechanical weakness due to carbon cluster formation at the interface between the nickel silicide layer and the silicon carbide body, leading to delamination and brittle fracture.

Innovation Solution

A bilayer of nickel-based and carbon-capturing metals (titanium, chromium, aluminum, or tantalum) is deposited on the silicon carbide body, followed by annealing to form a mixed silicide layer that stabilizes carbon as titanium carbide or ternary compounds, preventing carbon cluster formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If carbon is present at the interface between the nickel silicide layer and silicon carbide body, then the silicide layer forms during annealing, but carbon clusters form causing mechanical weakness

Engineering Contradiction:

Improvesilicide layer formationVSAvoidmechanical strength of silicide layer

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The carbon that would normally form harmful clusters at the interface is converted into a beneficial compound by reacting with the carbon-capturing metal layer to form stable carbides (TiC, Cr7C3, Al4C3, or TaC). This transforms the harmful carbon into a stable, non-cluster-forming compound that strengthens the interface.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The carbon-capturing metal layer serves as an intermediary that reacts with carbon to form stable carbides, preventing carbon cluster formation while allowing the nickel silicide layer to form properly. This intermediate reaction step converts the problematic carbon into a beneficial interface compound.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 process enhances the mechanical strength of the silicon carbide devices by eliminating carbon clusters, thereby preventing delamination and failure of the metal layer.

Implementation Method 1

forming a second layer of a second metal, different from the first metal, on the first layer to form a multilayer, the first or the second metal being nickel or a nickel alloy and forming a nickel-based layer, another of the first and the second metal being an X metal or an X-metal alloy capable to form stable compounds with carbon and forming an X metal-based layer

Methodology Applied

Scientific EffectCarbon capture: Absorption (physical)

Implementation Method 2

annealing the multilayer to form a mixed layer including nickel silicide and at least one of X carbide or a metal X-carbon ternary compound

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

annealing the multilayer to form a mixed layer including nickel silicide and at least one of X carbide or a metal X-carbon ternary compound

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 4

annealing the multilayer to form a mixed layer including nickel silicide

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12593630B2Process for manufacturing a silicon carbide device and silicon carbide device

Publication Date: 2026.03.31 STMICROELECTRONICS SRL

AI summary

A process for manufacturing a silicon carbide device from a body of silicon carbide having a back surface, wherein a first layer of a first metal is formed on the back surface of the body; a second layer of a second metal, different from the first metal, is formed on the first layer to form a multilayer, the first or the second metal being nickel or a nickel alloy and forming a nickel-based layer, another of the first or the second metal being a metal X, capable to form stable compounds with carbon and forming an X-based layer; and the multilayer is annealed to form a mixed layer including nickel silicide and at least one of X carbide or a metal X-carbon ternary compound.