Capacitive radio frequency discharges with a single ring-shaped narrow trench of various depths to enhance the plasma density and lateral uniformity

Abstract

Spatial structures of the electron density and temperature in ring-shaped hollow cathode capacitive rf plasma with a single narrow trench of 2 mm width have been investigated at various trench depths of D ¼ 5, 8, 10, 12, and 15 mm. It is found that the plasma density is increased in the presence of the trench and that the radial profile of the plasma density has a peak around the narrow hollow trench near the cathode. The density becomes uniform further away from the cathode at all trench depths, whereas the electron temperature distribution remains almost uniform. The measured radial profiles of the plasma density are in good agreement with a theoretical diffusion model for all the trench depths, which explains the local density increase by a local enhancement of the electron heating. Under the conditions investigated, the trench of 10 mm depth is found to result in the highest plasma density at various axial and radial positions. The results show that the radial uniformity of the plasma density at various axial positions can be improved by using structured electrodes of distinct depths rather than planar electrodes. V

Plasma parameters of RF capacitively coupled discharge: comparative study between a plane cathode and a large hole dimensions multi-hollow cathode

“…The HCE was found to be established when the product p.D falls within the range of 0.026-37 Torr cm [25][26][27]. This wide range of reported values necessitates more investigations on various configurations of MH cathodes depending on the diameter, depth and number of holes [28][29][30][31]. For example, the effects of the hole diameter (ranging from 0 to 10 mm), the driving frequency and gas composition on the RF MH cathode discharge have been studied by several authors [29,30,32,33].…”

Spatial profile of Al-ZnO thin film on polycarbonate deposited by ring-shaped magnetized rf plasma sputtering with two facing cylindrical Al2O3 – ZnO targets

“…The roughness R of the radial profile of the ion saturation current density is approximately 0.5, 0.38, 0.38, 0.34, 0.32 and 0.33 at z = 10, 20, 30, 40, 50 and 60 mm, respectively. Here, the roughness R is defined by the following expression 38)…”

RF magnetized ring-shaped plasma for target utilization obtained with circular magnet monopole arrangement

“…The bias voltage to the Langmuir probe compensated with an LC parallel filter circuit (choke) 3,4,13,15,19,23,40) to avoid the influence of potential fluctuations of the RF plasma on the probe I-V characteristics was changed from −70 to +70 V.…”

“…Capacitively coupled plasma (CCP) sources [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] driven by a radio frequency (RF) power supply at 13.56 MHz are widely used in functional film preparation and material processing owing to the simple experimental arrangement, easy maintenance, and large-diameter substrate processing. However, it is difficult to produce high-density plasma using a CCP source.…”