AVS 50th International Symposium
    Electronic Materials and Devices Monday Sessions
       Session EM+SC-MoA

Paper EM+SC-MoA4
Atomic Bonding and Electronic Changes at InGaAs/InP Heterojunctions

Monday, November 3, 2003, 3:00 pm, Room 321/322

Session: Defects and Interfaces in Electronic Materials and Devices
Presenter: P.E. Smith, The Ohio State University
Authors: P.E. Smith, The Ohio State University
S.H. Goss, The Ohio State University
S.T. Bradley, The Ohio State University
L.J. Brillson, The Ohio State University
M.K. Hudait, The Ohio State University
Y. Lin, The Ohio State University
S.A. Ringel, The Ohio State University
S.W. Johnson, Sandia National Laboratories
Correspondent: Click to Email
Lattice-matched In@sub 0.53@Ga@sub 0.47@As/InP heterojunctions have attracted considerable interest for many opto- and microelectronic applications. Achieving abrupt interfaces is difficult since both group III and V elements must be switched at the interface during MBE growth. To minimize structural defects, growers often employ a sequence of source switching such that new group V elements are switched on for brief exposure times before growth of subsequent layers. Interface-specific atomic bonding and diffusion can occur that can alter local electronic properties. We combined secondary ion mass spectrometry (SIMS) depth profiling with micro-cathodoluminescence spectroscopy (CLS) in cross section to measure atomic bonding and compositional changes and their effect on electronic properties. SIMS and CLS measurements of InGaAs-on-InP interfaces subjected to exposure times of 40, 80, 110, 140, and 170 sec reveal: (1) interface broadening (both As and P) that increases from < 5 to 15 nm with the length of time the InP surface is exposed to As prior to InGaAs growth, (2) InGaAs near band edge (NBE) emissions at ~0.79 and 0.80 eV, whose intensities shift to higher energies with proximity to the heterojunction on a submicron scale and become more evident with increasing As exposure time. These electronic changes suggest either lower In interface concentration and/or local defect formation - the latter consistent with increasing trap densities with As exposure measured via photoconductivity decay. Overall, local electronic structure at a lattice-matched III-V compound heterojunction depends sensitively on the competition of atomic species in the transition region during growth.