magnetroniplasmaa

Magnetron plasma refers to a high-density plasma generated in a magnetron discharge, most commonly in sputtering and plasma-processing systems. It is produced when a neutral gas, typically argon, is ionized in the presence of a strong magnetic field applied near a cathode, creating conditions that sustain the plasma near the target surface.

The key physical effect is the crossed electric and magnetic fields. The electric field accelerates electrons from the cathode, while the magnetic field confines them in closed orbits close to the surface, reducing losses to the chamber walls. The resulting high concentration of energetic electrons increases ionization efficiency, yielding a dense, quasi-neutral plasma.

Configurations include DC and RF magnetron discharges. Permanent magnets are arranged behind the target to form a magnetic flux density pattern that traps electrons over the erosion region. Typical operating pressures range from tens of millitorr to a few torr, with gas composition often argon and reactive gases for compound films. HiPIMS is a high-power variant that produces even higher plasma density.

Plasma properties include high density (about 10^18–10^19 m^-3 in many sputtering conditions), moderate electron temperature (a few electronvolts), and ion energies of a few to hundreds of electronvolts. The dense near-target plasma enhances sputtering yields and influences film growth, density, adhesion, stress, and microstructure.

Applications mainly lie in thin-film deposition and surface modification, notably magnetron sputtering of metals, nitrides, carbides, and oxides for hard coatings, optical coatings, and microelectronics packaging. The concept also underpins various plasma-surface engineering processes and analytical techniques.