Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 13: III-V Halbleiter II
HL 13.2: Vortrag
Freitag, 4. März 2005, 15:15–15:30, TU P-N202
Unusual Segregation of Antimony into InP in MOVPE — •Martin Leyer1, Stefan Weeke1, Frank Brunner2, Markus Pristovsek1, Markus Weyers2, and Wolfgang Richter1 — 1Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Hardenbergstraße 36 — 2Ferdinand-Braun-institut für Höchstfrequenztechnik, 12489 Berlin, Gustav-Kirchhoff-Str. 4
The GaAsSb/InP material system has promising advantages for an InP based DHBT (Double Heterostructure Bipolar Transistor) regarding bandstructure alignment and base sheet resis-tance. The optimization of the GaAsSb/InP interface is a critical issue since Antimony seg-regation is observed disturbing the formation of an abrupt interface. In order to investigate Sb segregation using Metalorganic Vapor Phase Epitaxy (MOVPE), InP surfaces where exposed to TMSb and afterwards overgrown with InP. The growth was monitored in situ with RAS (Reflec-tance Anisotropy Spectroscopy) and spectroscopic ellipsometry. Secondary Ion Mass Spec-troscopy (SIMS) was used to analyse the Sb content. The incorporation of Sb showed an unex-pected temperature dependence in the range from 500∘C to 600∘C. In SIMS a second Sb con-taining layer appeared on top of the Sb exposed layer after a certain thickness. This could be explained by the existence of a quasi-liquid InSb surface phase above the InSb melting tem-perature of 527∘C.