High Temperature Conductive Thin Films Using Aluminum Oxide
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies face challenges in producing high temperature-resistant, electrically conductive thin films for applications like piezoelectric components and surface acoustic wave (SAW) elements, as existing materials like aluminum and platinum suffer from oxidation, dewetting, and high production costs, limiting their usability above 300°C.
Innovation Solution
The development of thin films comprising a high temperature-resistant conductive metal with a melting point above 1500°C and aluminum oxide components, where aluminum oxide acts as a structuring agent and adhesive, diffusion barrier, and passivation layer, allowing for homogeneous mixing and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thick films (≥10 μm) of thermally resistant metals or electrically conductive compounds are used, then high temperature resistance is improved, but the films cannot be used in microstructure and nanostructure range
Solution Approach 1:
The patent changes the material composition parameters by combining high-melting-point metals (W, Mo, Ta, Nb) with aluminum and aluminum oxide in specific ratios. This compositional parameter change enables thin films to achieve both high-temperature resistance and electrical conductivity without requiring thick film structures
Solution Approach 2:
The patent creates composite thin-film materials combining multiple elements (high-melting-point metal + Al + Al2O3) to achieve properties that individual materials cannot provide alone. The composite structure provides simultaneous high-temperature stability, electrical conductivity, and structural integrity at thin film thicknesses
2Reliability
If aluminum is used as conductive material, then electrical conductivity and low density are improved, but oxidation occurs at high temperatures
Solution Approach 1:
Aluminum oxide acts as an intermediary protective layer that forms on the aluminum surface, preventing direct oxidation of the underlying aluminum metal. This intermediate Al2O3 layer maintains electrical conductivity while protecting against harmful oxidation at high temperatures
Solution Approach 2:
The aluminum oxide component creates an inert protective environment around the aluminum, effectively isolating it from oxygen exposure. This passive protection mechanism prevents oxidation without requiring active atmosphere control
3Temperature
If platinum is used as conductive material, then high temperature resistance is improved, but production costs increase
Solution Approach 1:
The patent replaces expensive platinum with more economical high-melting-point metals (tungsten, molybdenum, tantalum, niobium) that provide similar high-temperature resistance. The aluminum and aluminum oxide components further reduce material costs while maintaining performance
Solution Approach 2:
The patent changes the material selection parameters by choosing alternative metals with comparable melting points to platinum but lower costs. The optimized composition ratios balance performance requirements with manufacturing cost considerations
4Weight of moving object
If thin films are used for AOFW elements, then surface load is reduced and electro-acoustic coupling is improved, but structural stability at high temperatures deteriorates
Solution Approach 1:
The composite structure combines lightweight high-melting-point metals with aluminum oxide, providing both low surface load and high structural stability. The aluminum oxide framework enhances thermal stability while the metal components maintain electrical conductivity and mechanical strength
Solution Approach 2:
The patent optimizes the compositional parameters of the thin film, adjusting the ratios of metal to oxide components to achieve the desired balance between low density (for reduced surface load) and high-temperature structural stability
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 solution provides high temperature-resistant, low-density thin films with enhanced electrical conductivity, reducing production costs and enabling wider commercial application in high-temperature environments, while maintaining structural integrity and conductivity.
Implementation Method 1
unlike in previously known systems, aluminum and aluminum oxides are thoroughly and homogeneously mixed under the action of temperature with the conductive metal
Implementation Method 2
which, in contrast to previously known adhesive layers, can be used both as a structuring agent for the conductive metal and as an adhesive layer
Implementation Method 3
which, in contrast to previously known adhesive layers, can be used both as a structuring agent for the conductive metal and as an adhesive layer
Implementation Method 4
aluminum oxide components... can also be used as adhesive films, diffusion barriers, and/or passivation films
Data Source
AI summary
Electrically conductive thin film metallizations having continuous operating temperatures of 300° C. and more are of considerable practical interest for a number of technical applications, such as surface wave elements. Technical reasons and high production costs are a bar to the use of standard films. In order to remedy this, films including a mixture of a high-melting conductive metal and aluminum oxides, wherein in particular aluminum-rich non-stoichiometric aluminum oxides are used. The aluminum oxides act as components thermally stabilizing the conductive metal film; an optional proportion of chemically available aluminum can additionally alloy with the conductive metal and thereby enables essential film properties, such as the electrical conductivity to be specifically influenced. It is thus possible, using standard materials and methods of thin film deposition, in a cost-effective manner to produce highly electrically conductive, thermally resistant films having good structurability and comparatively low density for a wide range of different applications.