An improved Mo/n-GaAs contact by interposition of a thin Pd layer

The idea of limited reaction has been used to solve the adhesion and stability problems of Mo/n-GaAs and Pd/n-GaAs contacts. The structural and electrical properties of Mo/Pd/n-GaAs with different thicknesses of Pd layer, annealed from 300 degrees C to 500 degrees C for 30 min, were investigated. Adhesion of Mo to GaAs has been improved with the interposition of a thin Pd layer. With increasing Pd thickness, wider temperature ranges were achieved in which the contact showed rectifying Schottky behavior. The Schottky barrier heights were nearly constant below 300 degrees C and then dropped sharply at 450 degrees C, except for Mo(2000 AA)/Pd(200 AA)/n-GaAs diodes. The ideality factors converged to nearly unity at 300 degrees C and then increased sharply from 300 to 500 degrees C, except for Mo(2000 AA)/Pd(200 AA)/n-GaAs diodes, which maintained a nearly constant value of 1.34 from 400 to 500 degrees C.<
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