Ge/Pd/Cr contacts to gallium arsenide

Ge/Pd/Cr/n-GaAs contact structures have been examined in the contribution, in specific terms of the influence of the Cr layer thickness on electrical parameters and thermal stability of the structure. The lowest contact resistivity (1.4/spl times/10/sup -6/ /spl Omega/cm/sup 2/) has been measured in the case of the Ge(40)/Pd(20)/Cr(1) contact structure. The very thin Cr layer consists of small islands and the Pd layer has direct connection with the GaAs surface. This fact provides the same annealing temperature as in the case of the Ge/Pd structure. The Ge(40)/Pd(20)/Cr(4) and Ge(40)/Pd(20)/Cr(15) structures are Schottky at low annealing temperatures, they need high alloying temperature for ohmic-like conversion, but they are very stable.