Simulation of Neutral Particle Flow During High Power Magnetron Impulse

The behavior of neutral component of the plasma during high power impulse magnetron sputtering was studied. Movement of the neutral particles including sputtered metal (Ti) and Ar gas during an impulse (200 µs, 1 kA, 1 kV) has been simulated using direct simulation Monte Carlo method. When the discharge current reaches kA range, very strong gas rarefaction in the main plasma region occurs and the volume density of sputtered metal exceeds the gas density several times. This may contribute to the high ratio of metal ions to Ar ions observed in experiments. Rapid gas movement in the form of a shock wave toward the substrate results in a temporary increase in density and pressure of the substrate. This again influences both the deposition flux and the discharge behavior.