RFSputtern

RFSputtern, commonly referred to as RF sputtering, is a physical vapor deposition technique in which a target material is ejected by ions generated in a plasma driven by radio frequency energy. The process typically uses an inert gas such as argon and a vacuum chamber to create a dense plasma that bombards the target, releasing atoms that then deposit as a thin film on a substrate.

RF sputtering differs from direct current sputtering in that the radio frequency power allows sputtering of insulating as well as conductive targets. The RF field prevents charge buildup on insulating surfaces, enabling continuous material ejection. Most systems employ magnetron-enhanced configurations that use magnetic fields to confine electrons near the target, increasing plasma density and deposition rates.

Reactive sputtering is a common variant where a reactive gas such as oxygen or nitrogen is added to the sputtering atmosphere. This enables the formation of compound films, including oxides and nitrides, directly during deposition. Film composition can be tuned by adjusting gas ratios, power, and pressure, though reactive sputtering can introduce target poisoning and process instabilities.

Typical RF sputtering setups include a vacuum chamber, a target (the source material), a substrate holder, an RF power supply linked to the target, a gas inlet system, and sometimes magnets for magnetron configurations. Deposition rates vary from a few nanometers per minute to several tens of nanometers per minute, depending on power, pressure, and geometry.

Applications span protective and optical coatings, semiconductor device fabrication, mirrors, and hard coatings. Advantages include compatibility with insulating targets and good film uniformity, while limitations include relatively lower deposition rates and potential issues with reactive processes.