Comparison of Radio-Frequency Power Architectures for Plasma Generation

Abstract

Applications such as plasma generation require the generation and delivery of radio-frequency (rf) power into widely-varying loads while simultaneously demanding high accuracy and speed in controlling the output power across a wide range of power levels. Attaining high efficiency and performance across all operating conditions while meeting these system requirements is challenging, especially at high frequencies (10s of MHz) and power levels (1000s of Watts and above). This paper evaluates different architectures that directly address these challenges and enable efficient high-frequency operation over a wide range of output power levels and load impedances with the capability of fast output power control (e.g., within a few microseconds). We review techniques for achieving fast output power control and evaluate their suitability in efficient rf systems demanding accurate and fast control of output power. Two dc-to-rf system architectures utilizing the discussed power control techniques are presented to illustrate both the achievable performance benefits as well as their robustness to load impedance variation, and are compared using time-domain simulations. The results indicate the ability of the proposed architectures to maintain high efficiency (> 90%) across a very wide range of output power levels (e.g., over a factor of up to 85x) while being robust to load impedance variations.

Gas breakdown in radio-frequency field within MHz range: a review of the state of the art

“…Most MRF plasma sources [6] are generated by low-pressure MRF breakdown, including capacitively coupled plasmas (CCPs), inductively coupled plasmas (ICPs), Helicon plasmas, etc. These plasma sources are now being widely used in etching and deposition processes in the semiconductor industry and in electric propulsion technology in the aerospace industry [14][15][16][17].…”

Self-consistent simulation of the impedance matching network for single frequency capacitively coupled plasma

“…Recently, Bastami et al [9,10] have developed rf tunable matching network based on resistance compression network and phase-switched impedance modulation suitable for various industrial plasma processes. They also analyze the efficiency characteristics of the power control method in RF power architectures for plasma generation [11]. Actual matching data were analyzed and empirical impedance matching data are given with V-I measurements by Lee et al [12].…”

Multi-Inverter Discrete Backoff: A High-Efficiency, Wide-Range RF Power Generation Architecture

“…One important method for efficient and fast power control used in the proposed architecture is outphasing, or phaseshift control [1]- [5]. In this technique, the outputs of two or more PAs (or blocks of power-combined PAs) are combined via a lossless network and phase-shifted such that output power is modulated through the variation in the vector sum of combined PA outputs, with individual PAs seeing effective load impedance variations.…”