AVS 45th International Symposium
    Electronic Materials and Processing Division Friday Sessions
       Session EM-FrM

Paper EM-FrM3
Chemical Beam Epitaxy of GaAsN on GaAs (100)

Friday, November 6, 1998, 9:00 am, Room 316

Session: Fabrication and Characterization of Semiconductor Device Layers
Presenter: J.W. Rogers, Jr., University of Washington
Authors: J.W. Rogers, Jr., University of Washington
C.L. Aardahl, University of Washington
H.K. Yun, University of Washington
T.P. Pearsall, University of Washington
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Chemical beam epitaxy (CBE) has been used to deposit GaAsN on GaAs (100) at a growth pressure of order 5e-5 mbar and a substrate temperature of order 500C. Triethyl gallium, arsenic dimers, and an electron cyclotron resonance (ECR) nitrogen plasma were used as the Ga, As, and N sources, respectively. Secondary-ion mass spectrometry (SIMS) showed a maximum nitrogen content of 15% in the films grown in this study. Thermodynamic arguments predict that GaAs and GaN are immiscible due to the large discrepancy in atomic radii between As and N which leads to a positive heat of mixing for GaN and GaAs alloys. X-ray diffraction measurements show that higher nitrogen content does indeed result in phase segregation to a mixture of zinc-blende GaAs, zinc-blende GaN, and wurzite GaN depending on the growth conditions. However, unstrained alloys were deposited with a nitrogen content of up to 3%. Transmission electron micrographs and selected area diffraction patterns are used to discuss the orientation of segregated phases and ordering in the films. The effect of these morphological features on the band gap bowing parameter of the GaAsN system is discussed.