Parts | Days | Selection | Search | Downloads | Help
HL: Halbleiterphysik
HL 40: Poster III
HL 40.21: Poster
Friday, March 21, 1997, 11:00–14:00, Z
Thermal stability of engineered Schottky barriers — •L. Sorba1, M. Lazzarino1, C. Marinelli1, B. Müller1, A. Franciosi1, D. Chiola2, and F. Beltram2 — 1Laboratorio Nationale TASC-INFM, Area di Ricerca, Padriciano 99, I-34012 Trieste, Italy — 2Scuola Normale Superiore and Istituto Nazionale per la Fisica della Materia, I-56126 Pisa, Italy
Schottky barriers in Al/n-GaAs(001) diodes grown by molecular beam epitaxy (MBE) have been shown to be tunable through the fabrication of Si interface layers one to few monolayer-thick. Barriers as high (low) as 1.0-1.1eV (0.2-0.3eV) have been obtained by growing Si at the interface under an excess cation (anion) flux. The stability of the resulting diodes was studied by subjecting the diodes to annealing cycles in the 100-450oC temperature range and determining the barrier by means of x-ray photoemission and current-voltage transport measurements.
Diodes engineered for increased barrier heights remain stable for annealing temperature up to 300∘C, and a gradual degradation in the 350-450∘C temperature range corresponds to Si dissolution in the Al overlayer. Conversely diodes engineered for low barrier heights show lower stability, with a gradual increase in the barrier for annealing temperatures above 250∘C. Degradation in this case might involve temperature-enhanced randomization of the the Si-induced local interface dipoles which follows As-depletion of the interface.