Stagnation point flow analysis in an inductively coupled plasma reactor for advanced deposition techniques

초록

Plasma-Enhanced Atomic Layer Deposition (PEALD) is a critical technique for achieving high-quality thin films with precise thickness control and excellent conformality. In PEALD processes operating within the Torr pressure range, optimizing plasma transport and uniformity is essential to improve film deposition efficiency. One of the key factors influencing plasma behavior is the gas flow pattern, with stagnation point flow playing a significant role in determining electron and ion transport. However, understanding how process parameters—such as input power, gas pressure, and gas flow rate—affect plasma distribution remains a crucial challenge. This study employs a plasma-fluid model to numerically investigate the spatial distribution of plasma parameters in a PEALD reactor. Argon plasma is considered, as it is widely used in PEALD applications. The simulations incorporate a detailed Ar chemistry model, enabling accurate comparisons between plasma density predictions and experimental Langmuir probe measurements. Special attention is given to the ICP source region, where electron heating occurs, and the diffuser region, where the substrate is located. Through systematic analysis, we identify the effects of input power, gas pressure, and gas flow rate on plasma transport. Electron density increased by around 83% as power increased from 2 to 4.5 kW. Additionally, we propose geometric modifications to the reactor to improve plasma uniformity, addressing the issue of localized ion flux concentration at the reactor center. These findings provide valuable insights into optimizing PEALD conditions for enhanced plasma transport and uniform film deposition, paving the way for more efficient and scalable PEALD processes. © 2026 Elsevier B.V.

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