Identification of the volatile reaction products of the Cl{sub 2} + GaAs etching reaction

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena

DOI:https://doi.org/10.1116/1.586924· OSTI ID:161688

Su, C; Hou, H; Lee, G H ^[1]

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1. Columbia Univ., New York, NY (United States); and others

A molecular beam of Cl{sub 2} is reactively scattered from a single crystal GaAs (100) surface. Analysis of the mass spectra and of the angular and velocity distributions for the volatile reaction products over the surface temperature range 330-950 K shows that the major volatile reaction products are AsCl{sub 3}, As{sub 4}, As{sub 2}, GaCl{sub 3}, and GaCl. To correctly identify the GaCl{sub 3} and AsC1{sub 3} reaction products by mass spectrometry, the vibrational energy dependence of the daughter ion fragmentation patterns was measured by injecting GaCl{sub 3} and AsCl{sub 3} from a heated nozzle into the mass spectrometer. To convert the ion signals from the mass spectrometer (which are proportional to product density in the ionizer region) to quantities proportional to product flux from the surface, measurements of the product angular and velocity distributions were utilized. The relative product fluxes were then determined by assuming stoichiometric etching of GaAs. The five relative sensitivity factors determined from this fit are consistent with stoichiometric etching and achieve a chlorine mass balance to within 5% over the entire temperature range studied (330-950 K). The absolute reaction probability was determined by comparing the product fluxes and the flux of unreacted Cl{sub 2}, and the absolute etch rate was established by correlating the ion intensities measured for the evaporation of GaAs with the absolute evaporation rate reported in the literature. Finally, the effect of translational energy on the absolute etch rate and relative product flux distributions was measured by changing the rare gas diluent of the adiabatic expansion. No change in the etch rate or relative product yields was observed within experimental error for a variation of 0.025-0.15 eV in the translational energy directed along the surface normal. 58 refs., 23 figs., 4 tabs.

• OSTI ID: 161688
• Report Number(s): CONF-930115--
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 4 Vol. 11; ISSN JVTBD9; ISSN 0734-211X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
ARSENIC CHLORIDES
CHLORINE
ENERGY DEPENDENCE
ETCHING
GALLIUM ARSENIDES
GALLIUM CHLORIDES
MASS SPECTRA
MOLECULAR BEAMS
SCATTERING
VELOCITY