Accession Number : ADP007902

Title :   Adsorbed Layers in the Process of Chemical Vapor Deposition,

Corporate Author : OPTICAL SOCIETY OF AMERICA WASHINGTON DC

Personal Author(s) : Nishizawa, Jun-ichi

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : In chemical vapor deposition, surface migration of adsorbed species is an important factor which limit the minimum crystal growth temperature, since high substrate temperature enhances the surface migration of the adsorbate. But, high temperature process produces defects in the crystal. concerning this problem, photoepitaxy was proposed by the author in 1961. It has been applied to Si(2) and GaAs vapor phase epitaxy(3), resulting in higher crystal quality at a lower growth temperature. Photochemical processes allow the possibility that each elemental process can be individually controlled among the competitive processes by using a specific wavelength. Molecular layer epitaxy (MLE) is a crystal growth method using surface reactions of adsorption molecules and it is able to produce thin epitaxial films as accurate as a single atomic dimension. MLE of GaAs(3,4) Si(5) and A1GaAs were succeeded first in our experiments. It corresponds to the idea of atomic layer epitaxy using chemical reactants which was proposed by T. Suntola. In GaAs MLE, the material gases i.e. AsH3, TMG (or TEG) and dopant compound may adsorb on the specific site of the surface, when they are introduced onto the surface, alternately. Photo-excited process was also applied in MLE(8) the, irradiation can be independently undertaken at different crystal growth steps.

Descriptors :   *ADSORBATES, *CRYSTAL GROWTH, *VAPOR DEPOSITION, ADSORPTION, CRYSTALS, FILMS, HIGH TEMPERATURE, IRRADIATION, LAYERS, MATERIALS, MIGRATION, MOLECULES, QUALITY, SITES, SUBSTRATES, SURFACE REACTIONS, VAPOR PHASES, JAPAN, THERMAL PROPERTIES, SURFACE CHEMISTRY.

Subject Categories : Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE