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Title: Effect of electrode spacing on the density distributions of electrons, ions, and metastable and radical molecules in SiH{sub 4}/NH{sub 3}/N{sub 2}/He capacitively coupled plasmas

Semiconductor fabrication often requires the deposition of hydrogenated silicon nitride (SiN{sub x}H{sub y}) film using SiH{sub 4}/NH{sub 3}/N{sub 2}/He capacitively coupled plasma (CCP) discharge. As analysis of the discharge geometry is essential to understanding CCP deposition, the effect of electrode spacing on the two-dimensional distributions of electrons, ions, and metastable and radical molecules was analyzed numerically using a fluid model. The simulation shows that the spatial variations in the ionization rates near the sheath become more obvious as the electrode spacing increases. In addition, as molecule-molecule gas-phase reactions are significantly affected by the local residence time, large electrode spacings are associated with significant volumetric losses for positive ions. Consequently, an increase of the electrode spacing leads axial density profiles of ions to change from bell shaped to double humped. However, NH{sub 4}{sup +} persistently maintains a bell-shaped axial density profile regardless of the degree of electrode spacing. We set the mole fraction of NH{sub 3} to only 1% of the total flow at the inlet, but NH{sub 4}{sup +} is the most abundant positive ion at the large electrode spacings. As the gas flow can transport the radicals around the space between the electrodes, we found that radical density distributionmore » shifts toward the grounded electrode. The shift becomes pronounced as the electrode spacing increases. Finally, to validate our model, we compared the calculated deposition rate profile with the experimental data obtained along the wafer radius. According to our numerical results, the SiN{sub x}H{sub y} deposition rate decreases by approximately 16% when the electrode spacing increases from 9 to 20 mm.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Thin Film Technology Team, Samsung Electronics, Hwaseong-si 445-701 (Korea, Republic of)
  2. AE R&D Center, Kyungwon Tech, Inc., Seongnam-si 463-828 (Korea, Republic of)
  3. Department of Materials Science and Engineering, Kunsan National University, Kunsan-si 573-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22494639
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMMONIA; CATIONS; COMPUTERIZED SIMULATION; DEPOSITION; ELECTRIC DISCHARGES; ELECTRODES; ELECTRON DENSITY; EXPERIMENTAL DATA; GAS FLOW; HELIUM; HYDROGENATION; METASTABLE STATES; MOLECULE-MOLECULE COLLISIONS; MOLECULES; PLASMA; RADICALS; SEMICONDUCTOR MATERIALS; SILICON NITRIDES; THIN FILMS; TWO-DIMENSIONAL CALCULATIONS