Ion velocity distribution functions across a plasma meniscus

Here, we present laser-induced fluorescence measurements of an ion beam extraction angle and speed through a plasma-vacuum boundary as a function of plasma source parameters and bias potential applied to a wafer simulacrum outside the plasma. Ion temperature, velocity, and relative density are calculated from the measured ion velocity distribution function and are compared to a particle-in-cell model of the system. The measurements demonstrate that beam steering is feasible by varying plasma source density and extraction bias voltage. The focal point of the extracted beam, resulting from the plasma meniscus at the plasma-vacuum interface, depends on source density and extraction bias in a manner consistent with computational predictions.