Impact of charged species transport coefficients on self-bias voltage in an electrically asymmetric RF discharge

TL;DR

This study investigates how different charged species transport coefficients influence the self-bias voltage in RF hydrogen discharges using fluid modeling, highlighting the importance of ion mobility over electron transport in determining self-bias.

Contribution

It demonstrates the impact of ion mobility variations on self-bias voltage and shows fluid models can match hybrid models with proper ion transport parameters.

Findings

Self-bias is insensitive to electron transport coefficients.

Self-bias is highly sensitive to ion mobility.

Fluid models can be competitive with hybrid models when using self-consistent parameters.

Abstract

In this paper, we use a fluid model to simulate the excitation of a hydrogen radio-frequency discharge, and employ tailored voltage waveforms to assess the effect of charged species transport properties. Results of the fluid simulation are compared with experimental data and previous results obtained with a hybrid model. Several expressions for electron and ion transport coefficients are compared, and their impact on the self-bias potential is studied. The self-bias is shown to be insensitive to the choice of electron transport coefficients, while remarkably sensitive to variations in ion mobility. Besides, our results show that fluid models can be competitive with hybrid models, provided self-consistent ion transport models and rate constants are used.