In magnetron sputtering and plasma deposition processes, the power supply type plays a critical role in determining plasma stability, sputtering efficiency, film density, and process repeatability.
The most widely used power supply types are Radio Frequency (RF) power supplies and Medium Frequency (MF) power supplies, which differ significantly in terms of operating frequency, discharge mechanism, target compatibility, and process performance.
Selecting the appropriate power supply is essential for optimizing coating quality, production throughput, and system stability.
RF power supplies typically operate at 13.56 MHz and are primarily used for sputtering insulating targets such as SiO₂, Al₂O₃, and TiO₂.
Technical Features:
Maintains stable plasma discharge via an alternating electric field
Prevents charge accumulation on insulating target surfaces
Suitable for depositing dielectric films, optical coatings, and functional oxide layers
Provides excellent plasma uniformity for high-precision film applications
Advantages:
Compatible with non-conductive targets
Stable discharge and uniform sputtering
High compositional control and superior optical performance
Limitations:
Higher system cost
Lower power density and limited deposition rate
Complex impedance matching requirements
Medium Frequency (MF) power supplies typically operate in the 10–200 kHz range and are widely used in dual-magnetron systems and reactive sputtering processes, especially for metallic and metal-oxide coatings.
Technical Features:
Utilizes bipolar alternating discharge, minimizing charge accumulation on target surfaces
Effectively reduces arcing, improving process stability
Supports higher power density, enabling higher deposition rates
Well suited for large-area coating and industrial mass production
Advantages:
High deposition rate and superior throughput
Ideal for conductive targets and reactive sputtering
Enhanced arc suppression and operational reliability
Cost-effective with simplified maintenance
Limitations:
Not suitable for highly insulating targets
Plasma uniformity may require optimization through magnetic field and gas flow design
| Comparison Item | RF Power Supply | MF Power Supply |
|---|---|---|
| Operating Frequency | 13.56 MHz | 10–200 kHz |
| Target Compatibility | Insulating / Oxide Targets | Metallic / Reactive Targets |
| Deposition Rate | Medium to Low | High |
| Arc Suppression | Moderate | Excellent |
| Plasma Stability | High | High |
| System Cost | Higher | Lower |
| Typical Applications | Optical & Functional Films | Industrial & Decorative Coatings |
For highly insulating materials (optical and dielectric films), RF power supplies remain the preferred solution
For metal coatings, large-area deposition, and reactive sputtering (TiN, ITO, CrOx), MF power supplies offer superior throughput and cost efficiency
In high-volume industrial production, MF power supplies deliver better long-term process stability
For high-end optical and precision functional coatings, RF power supplies provide enhanced uniformity and compositional control.
RF and MF power supplies each offer distinct advantages in vacuum coating applications, with their suitability determined by target material properties, coating type, production capacity, and cost considerations.
As industrial coating continues to evolve, MF power supplies are becoming the mainstream choice for high-efficiency, high-consistency mass production, while RF power supplies remain indispensable for optical-grade and dielectric film deposition.
Looking ahead, hybrid power architectures and intelligent power control technologies are expected to further enhance process stability and coating performance.
-This article was published by vacuum coating equipment manufacturer Zhenhua Vacuum
Post time: Jan-27-2026