Diagnostics of a Multicusp-Assisted Inductively-Coupled Radio-Frequency Plasma Source for Plasma Immersion Ion Implantation

TL;DR

This study characterizes a multicusp-assisted inductively coupled RF plasma source for plasma immersion ion implantation, demonstrating stable operation, plasma recovery, and sheath dynamics analysis using advanced diagnostics.

Contribution

It provides detailed plasma diagnostics and validation of LIF for characterizing PIII plasma sources with multicusp configuration.

Findings

Enhanced plasma density at low pressure with multicusp design

Stable plasma operation with no perturbation at 0.8 mTorr

LIF potential profiles align with presheath theory

Abstract

In this article, we present a detailed characterisation of a multicusp-assisted inductively coupled RF plasma source for plasma immersion ion implantation (PIII). Using laser-induced fluorescence (LIF) and RF-compensated Langmuir probe diagnostics, we measured ion temperature T i and drift velocity v z in argon plasmas near an immersed electrode. The multicusp configuration enhances plasma density at low pressure, enabling stable operation down to 0.8 mTorr. Timeaveraged measurements show no detectable perturbation near the pulsed electrode, indicating full plasma recovery between high-voltage pulses. LIF-derived potential profiles match Riemann's presheath theory, and ion velocity distributions reveal acceleration consistent with sheath dynamics. These results support the use of LIF for steady-state characterisation of the bulk and presheath regions in PIII systems.