Low-Temperature Microwave Synthesis of Copper Germanide Thin Films
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Solution Overview
Problem
Conventional high-temperature annealing techniques for synthesizing semiconductor thin films, such as copper germanide (Cu3Ge), are unsuitable for plastic-based, light-weight, and flexible substrates due to high temperature requirements, leading to issues like undesired diffusion and pattern effects that degrade device performance.
Innovation Solution
A low-temperature microwave radiation process is used to convert deposited metal layers into intermetallic compounds like copper germanide, encapsulated in a metal oxide layer, which forms during the process, allowing for the formation of thin films with improved properties on silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing is used to synthesize copper germanide thin films, then the intermetallic compound forms with desired properties, but undesired diffusion into surrounding material occurs and device performance degrades
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (greater than 400°C) to low temperature (below 400°C, specifically 200-350°C range) to suppress undesired diffusion while still achieving copper germanide formation through extended annealing time
Solution Approach 2:
The patent uses periodic annealing cycles at low temperature, performing multiple annealing steps over extended periods (e.g., 30-120 minutes) to achieve the intermetallic compound formation without causing diffusion damage
2Manufacturing precision
If laser annealing is used to synthesize copper germanide thin films, then localized heating is achieved, but pattern effects occur due to incomplete coverage and degraded device performance
Solution Approach 1:
The patent replaces the mechanical laser scanning system with a uniform thermal field approach, using conventional annealing equipment that provides uniform heating across the entire substrate surface, eliminating pattern effects from partial coverage
Solution Approach 2:
The patent uses a universal annealing process that treats the entire substrate uniformly, making the process applicable to full-wafer processing without the spot-size limitations of laser annealing
3Reliability
If high temperature annealing greater than 400°C is used to synthesize copper germanide, then the intermetallic compound forms with low contact resistivity, but the process becomes unsuitable for plastic-based, light-weight, and flexible substrates
Solution Approach 1:
The patent changes the temperature parameter to below 400°C (specifically 200-350°C range) to enable processing of temperature-sensitive substrates like plastics while still achieving the desired copper germanide intermetallic compound formation through extended annealing time
Solution Approach 2:
The patent performs preliminary formation of the copper germanide layer at low temperature before subsequent device assembly, enabling the use of flexible and lightweight substrates that cannot withstand high temperature processing
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 method enables the production of copper germanide thin films with resistivity values of 5-20 μΩ-cm, providing improved device performance and protection from degradation, corrosion, and diffusion, while being energy-efficient and environmentally friendly.
Implementation Method 1
The first and the second metals in the film are converted into an intermetallic compound using microwave radiation
Implementation Method 2
a low-temperature microwave radiation process is used to convert deposited metal layers into intermetallic compounds
Implementation Method 3
The film of the intermetallic compound may be further encapsulated in a thin layer of metal oxide. The metal oxide thin layer may automatically form during microwave radiation
Data Source
AI summary
A method for preparing a device having a film on a substrate is disclosed. In the method, a film is deposited on a substrate. The film includes a first and a second metal. The first and the second metals in the film are converted to an intermetallic compound using microwave radiation. One example device prepared by the method includes a silicon substrate and a film on the substrate, wherein the film includes semiconducting copper germanide as the intermetallic compound.