SiC Silicide Contact Structure for Low-Resistance Electrode Interfaces

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Solution Overview

Problem

The formation of carbon clusters at the interface between silicon carbide and metal silicide layers in semiconductor devices increases contact resistance, leading to higher losses and potential separation issues between layers.

Innovation Solution

Incorporating a conductive layer with a silicide of nickel (Ni), palladium (Pd), or platinum (Pt) and performing heat treatment in an atmosphere containing carbon dioxide or atomic hydrogen to reduce carbon concentration in the metal silicide layer, thereby minimizing carbon cluster formation and maintaining low contact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal silicide layer is formed by causing the silicon carbide layer to react with a metal film, then contact resistance between the silicon carbide layer and metal electrode is reduced, but carbon clusters are precipitated at interfaces or within the metal silicide layer, increasing contact resistance

Engineering Contradiction:

Improvecontact resistanceVSAvoidcarbon cluster formation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of carbon precipitation into a beneficial process by intentionally introducing carbon into the metal silicide layer during formation. The carbon reacts with excess metal to form controlled carbon clusters that consume harmful excess metal and prevent larger harmful carbon cluster formation from unreacted silicon carbide carbon. This transforms the carbon from a harmful byproduct into a useful reactant that improves contact properties.

Inventive Principle:

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

Solution Approach 2:

The patent changes the carbon concentration parameter in the metal silicide layer from zero (conventional approach) to a controlled positive value (0.1-10 atomic percent). This parameter change fundamentally alters the formation mechanism, allowing carbon to react with excess metal during silicide formation and prevent harmful carbon cluster precipitation while improving electrical contact resistance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If excess carbon in the silicon carbide layer is precipitated as carbon clusters, then the reaction process is simplified, but contact resistance between the silicon carbide layer and metal electrode increases

Engineering Contradiction:

Improvecarbon precipitation processVSAvoidcontact resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-introducing carbon into the metal silicide layer before the silicon carbide carbon can precipitate harmfully. This preliminary carbon is strategically positioned to react with excess metal during the formation process, preventing the formation of large harmful carbon clusters while maintaining ease of manufacture through the same thermal processing steps.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If a large amount of carbon cluster is formed, then the metal silicide layer formation is complete, but contact resistance between the silicon carbide layer and metal electrode increases and layer separation may occur

Engineering Contradiction:

Improvemetal silicide layer formation completionVSAvoidcontact resistance and layer adhesion

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful complete reaction that produces large carbon clusters into a beneficial controlled reaction. By pre-introducing carbon, the excess metal is consumed in a controlled manner during formation, completing the metal silicide layer formation while preventing large harmful carbon cluster aggregation and maintaining low contact resistance and good adhesion.

Inventive Principle:

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

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

This configuration effectively decreases contact resistance between silicon carbide and metal electrodes, enhancing the reliability and performance of semiconductor devices by preventing carbon cluster formation and maintaining low resistivity.

Implementation Method 1

The metal silicide layer is formed by causing the silicon carbide layer to react with a metal film

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

performing heat treatment in an atmosphere containing carbon dioxide or atomic hydrogen to reduce carbon concentration in the metal silicide layer

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

heat treatment in an atmosphere containing carbon dioxide or atomic hydrogen to reduce carbon concentration

Methodology Applied

Scientific EffectCarbon removal reaction: Oxidation

Data Source

PatentUS11923420B2Semiconductor device, method for manufacturing semiconductor device, inverter circuit, driving device, vehicle, and elevator

Publication Date: 2024.03.05 KK TOSHIBA

AI summary

A semiconductor device according to an embodiment includes: a silicon carbide layer; a metal layer; and a conductive layer positioned between the silicon carbide layer and the metal layer, the conductive layer containing a silicide of one metal element (M) selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt), and the conductive layer having a carbon concentration of 1×1017 cm−3 or less.