Refractory Metal Nitride Capped Electrical Contact for III-V Semiconductors

Solution Overview

Problem

Conventional methods for forming electrical contacts on III-nitride power semiconductor devices, which use gold as a capping layer, are costly, lead to gold diffusion, and contaminate silicon fabrication processes, making monolithic integration with silicon devices challenging.

Innovation Solution

A refractory metal nitride capped electrical contact is developed, using a stack of titanium, aluminum, and a refractory metal nitride capping layer, such as titanium nitride, to reduce contamination risks and improve integration efficiency with silicon devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gold is used as a capping layer for electrical contacts on III-nitride devices, then desirable low SCLR values are achieved, but contamination of silicon fabrication processes occurs

Engineering Contradiction:

ImproveSCLRVSAvoidcontamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a refractory metal nitride capping layer as an intermediary between the aluminum electrode and the external environment. This capping layer serves as a mediator that provides the necessary electrical contact properties while preventing gold contamination of silicon fabrication processes, thus resolving the contradiction between achieving low SCLR and preventing contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces expensive gold with a more cost-effective refractory metal nitride capping layer. This substitution maintains the functional requirements for electrical contact performance while eliminating the contamination issues associated with gold, effectively using a cheaper alternative that serves the same protective function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If gold is used as a capping layer, then electrical contact performance is improved, but fabrication cost increases

Engineering Contradiction:

ImproveSCLRVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive gold with a more cost-effective refractory metal nitride capping layer. This substitution maintains the functional requirements for electrical contact performance while eliminating the contamination issues associated with gold, effectively using a cheaper alternative that serves the same protective function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If gold is used as a capping layer, then electrical contact properties are enhanced, but gold diffusion through the electrode stack occurs

Engineering Contradiction:

Improveelectrical contact propertiesVSAvoidgold diffusion

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces a refractory metal nitride capping layer as an intermediary between the aluminum electrode and the external environment. This capping layer serves as a mediator that provides the necessary electrical contact properties while preventing gold contamination of silicon fabrication processes, thus resolving the contradiction between achieving low SCLR and preventing contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9934978B2Method of fabricating an electrical contact for use on a semiconductor device

Publication Date: 2018.04.03 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

According to an embodiment, a method of manufacturing a group III-V semiconductor device includes forming a gate contact that includes an electrode stack including a first titanium layer, an aluminum layer over the first titanium layer, and a second titanium layer over the aluminum layer, and forming a biased reactive capping layer over the second titanium layer. The biased reactive capping layer includes biased reactive titanium nitride. The gate contact is a gate electrode that makes Schottky contact with the group III-V semiconductor device.