Molecular-beam study of gas-surface chemistry in the ion-assisted etching of silicon with atomic and molecular hydrogen and chlorine

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)

DOI:https://doi.org/10.1116/1.576790· OSTI ID:6800519

Chuang, M; Coburn, J W ^[1]

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1. IBM Almaden Research Center, San Jose, CA (USA)

Modulated molecular-beam mass spectrometry and quartz crystal microbalance techniques were used to study the etching of Si by the combinations of H/H{sub 2}, Cl/Cl{sub 2}, HCl, and Ar{sup +} ion bombardment at room temperature. Without ion bombardment, only H atoms etch Si spontaneously. While the addition of Cl or Cl{sub 2} stopped H etching instantaneously, the addition of HCl had no effect. With Ar{sup +} ion bombardment at 2 keV, the addition of HCl to the etching of Si with H, Cl, or Cl{sub 2} did not influence the etch rates. No DCl was observed when D atoms and HCl molecules were incident on Si simultaneously. This confirms that HCl does not dissociatively chemisorb on Si instantaneously. During ion-assisted etching, the addition of fluxes of H atoms, Cl atoms or Cl{sub 2} molecules increased the Si etch rate significantly. The Si etch rate for Cl atoms and Cl{sub 2} molecules was identical within experimental error provided the total chlorine flux was kept constant. The etch products observed were primarily SiCl{sub {ital x}}. The addition of H atoms to the ion-assisted etching of Si with Cl increased the etch rate the same amount as with Cl{sub 2} but four times more HCl was formed with Cl atoms. Several hydrogenated chlorosilane peaks were observed with the mass spectrometer and these peaks were larger with Cl{sub 2} than with Cl. The addition of either Cl or Cl{sub 2} to the H/Ar{sup +}/Si system decreased the etch rate. These observations suggest the recombination of H and Cl to form HCl is not rate limiting in these etching processes.

• OSTI ID: 6800519
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA) Journal Issue: 3 Vol. 8:3; ISSN JVTAD; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ARGON IONS
ATOMIC BEAMS
BEAMS
CHARGED PARTICLES
CHLORINE
COLLISIONS
ELEMENTS
ETCHING
HALOGENS
HYDROGEN
ION COLLISIONS
IONS
MASS SPECTROSCOPY
MOLECULAR BEAMS
NONMETALS
SEMIMETALS
SILICON
SPECTROSCOPY
SURFACE FINISHING