Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 40: Halbleiteroberflächen und -grenzflächen

O 40.4: Talk

Thursday, March 11, 2004, 16:30–16:45, H45

In-Situ- and UHV-Investigation of MOCVD-Grown GaAsSb-Interfaces — •Zadig Kollonitsch, Matthias Neges, Kristof Möller, Frank Willig, and Thomas Hannappel — Hahn-Meitner-Institut, SE4, Glienicker Strasse 100, D-14109 Berlin, Germany

The effect of antimony segregation at surfaces and interfaces complicates the application of such layers in semiconductor devices. To improve interface abruptness various protocols may be employed and investigated at the atomic scale. Lattice matched GaAs_0.51Sb_0.49/InP(100)-layers were grown by MOVPE at 770K. The surface and interface reconstruction was monitored with reflectance anisotropy/difference (RAS/RDS) spectroscopy. The RA-Spectrum of the As-rich GaAsSb(100) surface showed different features compared to that of the Sb-rich surface. The in-situ signals indicated that the surface was Sb-rich during growth and turned preferably into an As-rich surface after growth. Contamination free sample transfer into ultrahigh vacuum (UHV) allowed the correlation of the in-situ signals with LEED and UV-photoelectron spectroscopy (UPS). The LEED pattern of As-rich GaAsSb(100) showed a c(4 × 4) reconstruction with bright spots, whereas the LEED pattern of Sb-rich GaAsSb(100) showed a (1 × 3)-like reconstruction with weak spots. Possible models for the surface reconstructions are discussed. Results are presented for the growth of InP/GaAsSb heterojunctions on As- and Sb-rich GaAsSb(100) surfaces.