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Kinetic modelling of GaAs chemical beam epitaxy
A633 Surface Science 293 (1993) 93-106 North-Holland
Kinetic modelling of GaAs chemical beam epitaxy V.M. Donnelly a and A. Robertson, Jr. b AT& T Bell Laboratories, 600 Mountain Avenue, Murray Hill, NJ 07974-2070, USA b AT& T Bell Laboratories- Engineering Research Center, P.O. Box 900, Princeton, NJ 08540, USA a
Received 15 February 1993; accepted for publication 12 April 1993 We report results of kinetic modelling of the growth of GaAs by chemical beam epitaxy (CBE) with an effusive beam of triethylgallium (TEGa). The model is an extension of one reported previously and includes new reactions and Arrhenius parameters reported in recent UHV surface studies. The model provides excellent fits to growth rates measured as a function of substrate temperature and TEGa beam flux. The major conclusions are: (1) at low temperature the increase in growth rate with temperature is due to an increase in the rate limiting desorption of hydrocarbon products (C2H 4 and C2H5), and (2) at high temperature, the fall-off in growth rate is a consequence of precursor-mediated adsorption of TEGa, i.e. as temperature increases, desorption of TEGa begins to compete with dissociation.
Surface Science 293 (1993) 107-113 North-Holland
Surface polariton modes on anisotropic etched surfaces of III-V semiconductors with different morphology N.L. Dmitruk, T.R. Barlas and E.V. Pidlisnyi Institute of Semiconductors, Ukrainian Academy of Sciences, Prospect Nauki 45, 252028 Kiev, Ukraine Received 2 February 1993; accepted for publication 13 April 1993 The surface relief of semi-insulating InP and GaAs has been investigated for several stages of three different types of morphology (grooves, dendrites, pyramids). Changes in dispersion and damping of surface phonon polaritons have been studied by the attenuated total reflection (ATR) method in the far-infrared region of 25-35 ~m. Geometric parameters of surfaces have been independently measured by profilometry and then, after statistical treatment, they have been used for a numerical calculation of the changes in surface polariton damping. The results of the calculations were compared with the data obtained by the ATR method. An anomalous small damping of surface modes on the grooves-type microrelief of InP and a very large intensity of vibration modes of surface oxide on the dendrite-type microrelief of GaAs have been observed.
Surface Science 293 (1993) 114-122 North-Holland
On the infrared spectrum of atoms and molecules adsorbed on a metal surface M. Franz a,b and Y.R. Wang a,c a Center for Photoinduced Charge Transfer, University of Rochester, Rochester, IVY 14627, USA b Department of Physics and Astronomy, University of Rochester, Rochester, N Y 14620, USA c Xerox Webster Research Center, 800 Phillips Road, 0114-41D, Webster, N Y 14580, USA Received 2 February 1993; accepted for publication 19 April 1993 The infrared absorption spectrum is calculated for atoms and molecules adsorbed on a metal surface to include the strong rehybridization between the electronic states of the metal and the adsorbate atomic (molecular) orbital. We find that although rehybridization does not significantly alter the character of line shape, it leads to the renormalization of the electron-vibrational mode coupling constant. Our analysis also shows that the oscillator strength of the adsorbate vibrations is acquired from the electronic transitions between the states below the Fermi level of the metal and the empty orbital of the adsorbate.
Kinetic modelling of GaAs chemical beam epitaxy V.M. Donnelly a and A. Robertson, Jr. b AT& T Bell Laboratories, 600 Mountain Avenue, Murray Hill, NJ 07974-2070, USA b AT& T Bell Laboratories- Engineering Research Center, P.O. Box 900, Princeton, NJ 08540, USA a
Received 15 February 1993; accepted for publication 12 April 1993 We report results of kinetic modelling of the growth of GaAs by chemical beam epitaxy (CBE) with an effusive beam of triethylgallium (TEGa). The model is an extension of one reported previously and includes new reactions and Arrhenius parameters reported in recent UHV surface studies. The model provides excellent fits to growth rates measured as a function of substrate temperature and TEGa beam flux. The major conclusions are: (1) at low temperature the increase in growth rate with temperature is due to an increase in the rate limiting desorption of hydrocarbon products (C2H 4 and C2H5), and (2) at high temperature, the fall-off in growth rate is a consequence of precursor-mediated adsorption of TEGa, i.e. as temperature increases, desorption of TEGa begins to compete with dissociation.
Surface Science 293 (1993) 107-113 North-Holland
Surface polariton modes on anisotropic etched surfaces of III-V semiconductors with different morphology N.L. Dmitruk, T.R. Barlas and E.V. Pidlisnyi Institute of Semiconductors, Ukrainian Academy of Sciences, Prospect Nauki 45, 252028 Kiev, Ukraine Received 2 February 1993; accepted for publication 13 April 1993 The surface relief of semi-insulating InP and GaAs has been investigated for several stages of three different types of morphology (grooves, dendrites, pyramids). Changes in dispersion and damping of surface phonon polaritons have been studied by the attenuated total reflection (ATR) method in the far-infrared region of 25-35 ~m. Geometric parameters of surfaces have been independently measured by profilometry and then, after statistical treatment, they have been used for a numerical calculation of the changes in surface polariton damping. The results of the calculations were compared with the data obtained by the ATR method. An anomalous small damping of surface modes on the grooves-type microrelief of InP and a very large intensity of vibration modes of surface oxide on the dendrite-type microrelief of GaAs have been observed.
Surface Science 293 (1993) 114-122 North-Holland
On the infrared spectrum of atoms and molecules adsorbed on a metal surface M. Franz a,b and Y.R. Wang a,c a Center for Photoinduced Charge Transfer, University of Rochester, Rochester, IVY 14627, USA b Department of Physics and Astronomy, University of Rochester, Rochester, N Y 14620, USA c Xerox Webster Research Center, 800 Phillips Road, 0114-41D, Webster, N Y 14580, USA Received 2 February 1993; accepted for publication 19 April 1993 The infrared absorption spectrum is calculated for atoms and molecules adsorbed on a metal surface to include the strong rehybridization between the electronic states of the metal and the adsorbate atomic (molecular) orbital. We find that although rehybridization does not significantly alter the character of line shape, it leads to the renormalization of the electron-vibrational mode coupling constant. Our analysis also shows that the oscillator strength of the adsorbate vibrations is acquired from the electronic transitions between the states below the Fermi level of the metal and the empty orbital of the adsorbate.