AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS1+EM-WeA

Paper SS1+EM-WeA3
STM-Study of the Absorption of Molecular Oxygen on GaAs(100)

Wednesday, October 27, 1999, 2:40 pm, Room 606

Session: Semiconductor Surface Science
Presenter: P. Kruse, University of California, San Diego
Authors: P. Kruse, University of California, San Diego
J.G. McLean, University of California, San Diego
A.C. Kummel, University of California, San Diego
Correspondent: Click to Email
There is currently a strong interest in making GaAs-oxide interfaces with very low defect densities to enable the use of GaAs-based FET technology. The interaction of oxygen with the GaAs surface plays an important role in this process. In this study, high-resolution scanning tunneling microscopy (STM) was used to image the chemisorption sites of molecular oxygen on the three most common reconstructions of the GaAs(100) surface, c(2x8), 6x6 and c(8x2) . All studies were performed at room temperature. The sticking probability was greatest on the surfaces with As-As dimer bonds. Even though the molecular oxygen prefers to initially react with the empty dangling bonds of the Ga atoms, after dissociation the oxygen atoms seek to form bridge bonds between an electron rich As atom from an As-As dimer and a second atom, either As or Ga. These dimerized As atoms do not exist in the c(8x2) reconstruction, hence the greater inertness of that surface. This is in contrast to the reaction of these surfaces with halogens which only need to form one bond per halogen atom and equally attack all reconstructions.