HIGH-TEMPERATURE STABLE IR-AL N-GAAS SCHOTTKY DIODES - EFFECT OF THE BARRIER HEIGHT CONTROLLING/

We report on novel Ir-Al/n-GaAs Schottky contact systems based on sequ entially evaporated Ir-Al multilayers which enable us to control the b arrier height at the interface with annealing temperature. Auger depth profiling and Rutherford backscattering methods were applied to analy ze the Ir-Al composition and the interfacial reaction stability. An in crease of the barrier height with annealing temperature has been indic ated for all the Schottky contact systems. Barrier heights as high as 0.95 V were measured for annealed Schottky diodes with the first alumi num or very thin iridium interfacial layer. A model of the barrier hei ght enhancement based on a solid phase epitaxy of a graded AlxGa1-xAs layer at the interface at elevated annealing temperatures was consider ed to explain the electrical properties of the contacts. The model con tributions to the formation of a metal/AlxGa1-xAs/GaAs heterojunction diodes with required barrier height and thermal stability are discusse d. (C) 1996 American Vacuum Society.