Sputtering and evaporation both belong to physical vapor deposition, but the material reaches the substrate in different ways. That difference influences film density, composition control, step coverage, rate and the design of the vacuum system.
Evaporation is strongly line-of-sight
Material is heated until it produces vapor, then travels toward cooler surfaces. Thermal sources are simple for suitable materials; electron-beam sources can handle materials requiring higher source temperatures. Fixtures and substrate rotation are important when coating larger areas or three-dimensional parts.
Sputtering begins with a plasma
Process-gas ions strike a target and eject atoms. Magnetron fields increase plasma density near the target. The arriving species can carry more energy than a typical evaporated flux, which may help produce dense films but can also affect sensitive substrates.
Composition needs application-specific evidence
Neither method automatically preserves the source composition. Reactive gases, target chemistry, preferential loss, substrate heating and re-sputtering can alter the layer. For compounds, ask how stoichiometry is monitored and how often the result is checked.
Compare the complete operating cycle
Deposition rate is only one part of throughput. Include pump-down time, pre-cleaning, target conditioning, source refill or target change, chamber cleaning and recovery after maintenance. The best method is the one that meets film requirements through a stable, maintainable process window.
