Thickness inhomogenities and growth mechanisms of GaP heteroepitaxy

ORAL

Abstract

We report comparative studies of the heteroepitaxy of GaP by organometallic chemical vapor deposition (OMCVD) using trimethylgallium (TMG) and phosphine (PH3) sources on (001) GaAs, thermally generated SiO2, (001) Si, and nanoscopically roughened Si surfaces. Inadvertent indirect but important data were also obtained from the polycrystalline GaP deposited on the Mo susceptor surrounding the 2 in. wafers. We found that the thicknesses of the deposited GaP films increases or decreases exponentially toward the edge of the wafers. This dependence is incompatible with the common explanation of gas-phase depletion of the precursors. Starting with the diffusion equation, we derive analytic expressions that describe the thickness variations in terms of the diffusion parameters, and evaluate the diffusion length quantitatively. We show that the cause is due to differences in chemical reactivities of the various surfaces, especially the different catalytic effects that they exert on PH3 decomposition. The results also show that different parts of the surface, including the susceptor, are in constant contact with each other during growth through gas-phase diffusion, and that deposition occurs via a precursor that involves both Ga and P. We propose a model for GaP growth based on the formation mechanism of this precursor.

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Authors

  • Xiang Liu

    North Carolina State University, Department of Physics, North Carolina State University

  • Jaetae Seo

    NC A\&T State University, Penn State University, The Ohio State University, Wright State University, AFRL/RYHC Hanscom AFB MA 01731, Harvard University, The College of William \& Mary, NCSU Near-field Optics Lab, University of North Carolina at Chapel Hill, Weizmann, PTB, Braunschweig, UMass, TUNL/Duke, UConn, UConn/TUNL, University of North Carolina, Chapel Hill, North Carolina State University, Brimrose Corporation of America, Hampton University, Elizabeth City State University, Department of Physics, Florida A\&M University, Tallahassee, Florida-32307, Department of Physics, University of Rajshahi, Rajshahi-6205, Bangladesh, Department of Physics, University of Rajshahi, Rajshah-6205, Bangladesh, Department of Physics, University of Rajshahi, Rajshahi-6250, Bangladesh, Department of Physics, University of Rajshahi-6205, Bangladesh, Alabama A\&M University, Fachbereich C-Mathematik und Naturwissen-Schaften, Bergische Universitat Wuppertal, D-42097, Wuppertal, Germany, NC State University, College of William and Mary, Department of Physics, N.C. State Univeristy, Research Triangle Institute, NCSU Physics, Pennsylvania State University, Tsinghua University, Lawrence Berkeley National Laboratory, Vanderbilt University, LSU, UNIRIB, U. Tenn., ORNL, Miss. St., University of North Carolina at Chapel Hill and Triangle Universities Nuclear Laboratory, NCA\&T, Duke, NCCU, UNC-Chapel Hill, Department of Physics, North Carolina State University, Department of Chemistry, North Carolina State University, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hil, North Carolina School of Science and Mathematics, Department of Physics, Elon University, Dept. of Physics - UNC - Chapel Hill, Nanyang Technological University, School of Materials Sciences and Engineering, Singapore, Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255, USA, Argonne National Laboratory, Department of Physics, Hampton University, Hampton, VA 23668, Korea Research Institute of Standards and Science, Daejeon, 305-600, South Korea, Department of Chemistry, Gyeongsang National University, Jinju 660-701, South Korea, Electronics and Telecommunications Research Institute, Daejeon, 305-700, South Korea, Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609

  • David Aspnes