Laser Ionization Mass Spectrometry Measurements of Arsenic Sticking and Incorporation During GaAs (100) Homoipataxy

Published

April 1, 1997

Author(s)

Lisa S. Ott, S M. Casey, S R. Leone

Abstract

The fluxes of Ga, As₄ and As₂ desorbed or scattered from a GaAs (1 0 0) surface are monitored with laser single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) during homoepitaxy of GaAs(1 0 0) with incident As₄ and Ga molecular beams. When the Ga flux is opened to the surface under a constant incident arsenic flux, the observed decrease in the scattered As₄ and As₂ mass signals are a measure of the arsenic incorporation into the growing GaAs layers. Simultaneous reflection high-energy electron diffraction (RHEED) oscillations measured during epitaxy are used to quantify the arsenic and gallium fluxes. The sticking probability for As₄ molecules on the GaAs surface is measured over a range of As₄ and Ga incident fluxes and for the substrate temperature range 600-900 K. At substrate temperatures and under flux conditions in which RHEED specular beam intensity oscillations are observed during epitaxy, the maximum sticking probability for As₄ exceeds the often-quoted value of 0.5, with values observed greater than 0.8. At higher substrate temperatures and under flux conditions in which Ga islands are present on the GaAs surface, the maximum sticking probability of As₄ is 0.5. The sticking probability of As₄ on the GaAs surface decreases with increasing surface temperature.

Citation

Journal of Crystal Growth

Volume

181

Pub Type

Journals

Keywords

arsenic, GaAs(100), laser ionization, mass spectrometry, RHEED

Citation

Ott, L. , Casey, S. and Leone, S. (1997), Laser Ionization Mass Spectrometry Measurements of Arsenic Sticking and Incorporation During GaAs (100) Homoipataxy, Journal of Crystal Growth (Accessed September 13, 2024)