Andrew Li
14. März 2025
Magnetron sputtering and thermal evaporation are both widely used physical vapor deposition (PVD) techniques for thin-film coating. Although both methods can coat similar materials (such as carbon targets for sputtering and carbon rods for evaporation), each has unique strengths in semiconductor and optical applications. Here, we compare these two techniques using Vision Precision Instruments’ VPI SD-650MH magnetron sputter coater and SD-100AF high-vacuum thermal evaporator to help you determine the best approach for your specific requirements.
Technology Principles
Magnetron sputtering uses high-energy ions from a plasma to bombard a solid target, ejecting atoms or molecules onto the substrate to form a thin film. This technique provides coatings with excellent density and strong adhesion, particularly suitable for high-melting-point materials, alloys, and compounds. The VPI SD-650MH magnetron sputter coater offers stable and precise thin-film deposition through single-target, dual-target, or multi-target setups, with high vacuum levels up to 5×10⁻⁵ Pa, making it ideal for semiconductor electrodes, interconnects, and conductive ITO films.
Thermal evaporation involves heating materials until they vaporize or sublime in a high vacuum, then condensing onto a substrate. This simpler, faster, and cost-effective method is especially suited for quick deposition of single-element materials such as gold, silver, and aluminum. VPI’s SD-100AF thermal evaporator provides ease of operation, making it well-suited for rapid prototyping and everyday laboratory coating tasks.
Applications in Semiconductors
In semiconductor manufacturing, film uniformity, density, and reliability are critical. Magnetron sputtering excels here, providing superior coating of microstructures, electrodes, and barrier layers (e.g., titanium/titanium nitride), essential for ensuring consistent coverage within microscopic features. Thus, magnetron sputtering has become the preferred method for modern chip fabrication.
Thermal evaporation, on the other hand, remains valuable for rapid prototyping of simple metallic electrodes (aluminum or gold on silicon wafers), especially useful in early-stage research or cost-sensitive projects. It offers an economical solution without compromising speed.
For example, researchers using VPI equipment for semiconductor sensors prefer magnetron sputtering for high-quality Ti/Al electrode layers due to better adhesion and durability. However, for preliminary tests, thermal evaporation is favored for quickly applying aluminum or gold electrodes, speeding up the development process.
Applications in Optics
Optical coatings—such as lens coatings, filters, and anti-reflective layers—frequently utilize thermal evaporation for rapid, cost-effective production. For large-scale manufacturing of simpler optical components, thermal evaporation remains popular due to its speed and cost-effectiveness.
Yet, magnetron sputtering offers superior performance for advanced optical applications, including high-reflectivity laser mirrors and complex multilayer filters. Films produced by magnetron sputtering are denser and more resistant to environmental factors like humidity, making it the preferred method for high-end optics.
For instance, one of VPI’s international customers uses the SD-650 magnetron sputtering system to produce highly stable ultraviolet bandpass filters. These coatings exhibit enhanced stability and performance compared to traditional thermally evaporated multilayer coatings, particularly in varying humidity conditions.
Choosing the Right Method
Magnetron sputtering (e.g., VPI SD-650 or 320MH series) is best when high density, strong adhesion, and precise control are essential, particularly for refractory metals, alloys, or complex compounds.
Thermal evaporation (e.g., VPI SD-100AF) is preferable when rapid coating, simplicity, and lower cost are priorities, especially for pure metal films (gold, silver, aluminum).
For heat-sensitive substrates (plastics or organic materials), the choice between sputtering and evaporation depends on specific sensitivity and application requirements.
For semiconductor and advanced optical applications, magnetron sputtering typically remains the leading choice due to consistency and superior film properties.
Both magnetron sputtering and thermal evaporation methods have successfully served various lab and industrial applications using VPI equipment. Understanding each method's characteristics enables researchers and engineers to make informed decisions based on practical needs, ensuring optimal cost-effectiveness and performance.
Selecting the right coating method is essential for maximizing the quality and efficiency of your projects.