GaN Semiconductor Electrode Buffer Layer Copper Diffusion
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Solution Overview
Problem
In semiconductor devices with high electron mobility transistors, copper atoms from the circuit layer diffuse into the main body, leading to poor electrical properties and reliability due to copper's high activity, especially when aluminum is used as a material for the ohmic contact layer.
Innovation Solution
A semiconductor device with a GaN-based main body and electrode structures that include an ohmic contact layer made of titanium, aluminum, or their alloys, and a buffer layer of titanium or tungsten nitride, which prevents copper atom diffusion by separating the copper-based circuit layer from the main body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as the main material for the circuit layer to reduce manufacturing cost and improve electrical conductivity, then manufacturing cost is reduced and electrical conductivity is improved, but copper atoms diffuse into the main body causing poor electrical properties and inferior reliability
Solution Approach 1:
The patent introduces a buffer layer made of titanium nitride or tungsten nitride as an intermediary between the copper-based circuit layer and the GaN-based main body. This buffer layer acts as a diffusion barrier that prevents copper atoms from migrating into the main body while maintaining electrical conductivity, thereby eliminating the harmful diffusion effect without sacrificing the benefits of copper material.
2Use of energy by moving object
If aluminum is used as the ohmic contact layer material to reduce cost, then manufacturing cost is reduced, but electrical conductivity and thermal conductivity are poor leading to over-heating and high power consumption
Solution Approach 1:
The patent employs a composite electrode structure consisting of multiple layers: an aluminum-based ohmic contact layer in direct contact with the GaN main body, a copper-based circuit layer for low-resistance current transmission, and a titanium nitride or tungsten nitride buffer layer as a diffusion barrier. This composite structure combines the advantages of each material while mitigating their individual disadvantages.
3Volume of moving object
If the electrode structure is minimized in size to reduce device footprint, then device size is reduced, but over-heating occurs due to poor thermal conductivity of aluminum
Solution Approach 1:
The multi-layer composite electrode structure incorporates copper with high thermal conductivity to conduct heat away from the minimized device structure, preventing overheating while maintaining compact dimensions. The copper-based circuit layer serves dual purposes of electrical conduction and thermal management.
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 buffer layer effectively prevents copper atom diffusion, maintaining semiconductor properties and ensuring high reliability by maintaining stable current values, power requirements, and electrical conductivity.
Implementation Method 1
a buffer layer that is formed on the ohmic contact layer opposite to the main body... The buffer layer effectively prevents copper atom diffusion
Data Source
AI summary
A semiconductor device includes a main body made of a GaN-based semiconductor material, and at least one electrode structure. The electrode structure includes an ohmic contact layer that is formed on the main body, a buffer layer that is formed on the ohmic contact layer opposite to the main body, and a circuit layer that is made of a copper-based material and that is formed on the buffer layer opposite to the ohmic contact layer. The ohmic contact layer is made of a material selected from titanium, aluminum, nickel, and alloys thereof. The buffer layer is made of a material different from the material of the ohmic contact layer and selected from titanium, tungsten, titanium nitride, tungsten nitride, and combinations thereof.