GaN Drain Structure With GaN:C Buffer for Silicon Leakage Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Gallium nitride (GaN) drains in transistors face defects and current leakage due to lattice mismatch with silicon substrates, and the use of aluminum nitride liners increases resistance.

Innovation Solution

Depositing gallium nitride and carbon (GaN:C) composite layers as a buffer between GaN drains and silicon substrates, and implanting silicon in aluminum nitride liners to reduce contact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If gallium nitride is deposited directly on silicon substrate, then the transistor breakdown voltage is improved, but defects and current leakage occur due to lattice mismatch

Engineering Contradiction:

Improvebreakdown voltageVSAvoiddefects and current leakage

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

A buffer layer comprising gallium nitride and carbon is introduced between the silicon substrate and the gallium nitride drain. This intermediary buffer layer accommodates the lattice mismatch between silicon and gallium nitride, reducing defects and current leakage while allowing the high breakdown voltage benefit of gallium nitride to be realized.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer layer is formed as a composite material combining gallium nitride and carbon. This composite structure leverages the beneficial properties of both materials: gallium nitride provides the necessary crystal structure compatibility and high breakdown voltage, while carbon helps accommodate lattice mismatch and reduce defects.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If aluminum nitride liner is used to reduce lattice mismatch, then manufacturing precision is improved, but contact resistance increases

Engineering Contradiction:

Improvelattice mismatch reductionVSAvoidcontact resistance

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Silicon is implanted into the aluminum nitride liner to modify its electrical properties. This parameter change (adding silicon) reduces the contact resistance at the interface between the aluminum nitride liner and the n-doped channel, while the aluminum nitride liner continues to provide lattice mismatch reduction.

Inventive Principle:

Principle #35Parameter changes

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 GaN:C buffer reduces defects and current leakage, while implanted silicon in the liners improves electrical performance by reducing contact resistance.

Implementation Method 1

gallium nitride has a significant lattice mismatch with silicon (Si), which is typically used to form the substrate in which the drain will be formed

Methodology Applied

Scientific EffectLattice mismatch:

Implementation Method 2

implanting silicon in aluminum nitride liners to reduce contact resistance

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Data Source

PatentUS20250194188A1Gallium nitride drain structures and methods of forming the same

Publication Date: 2025.06.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Depositing gallium nitride and carbon (GaN:C) (e.g., in the form of composite layers) when forming a gallium nitride drain of a transistor provides a buffer between the gallium nitride of the drain and silicon of a substrate in which the drain is formed. As a result, gaps and other defects caused by lattice mismatch are reduced, which improves electrical performance of the drain. Additionally, current leakage into the substrate is reduced, which further improves electrical performance of the drain. Additionally, or alternatively, implanting silicon in an aluminum nitride (AlN) liner for a gallium nitride drain reduces contact resistance at an interface between the gallium nitride and the silicon. As a result, electrical performance of the transistor is improved.