Investigation of Alloyed Ohmic Contacts in Epitaxial Tellurium-Doped Gallium Arsenide Layers

Resumo

The conditions for the growth of epitaxial layers are considered and the resistance of alloyed ohmic contacts to tellurium-doped gallium arsenide layers is studied. The use of the (AuGe eutectic alloy)-Ni–Au composition alloy of ohmic contacts to the gallium arsenide layers with electron conductivity, including use as a contact layer of a narrow-band (In_0.5Ga_0.5As), makes it possible to achieve a resistance of 10^–7 Ohm cm², in the best case; however, this leads to a deterioration of the surface morphology. In this paper, we study the issues of doping the GaAs contact layer by tellurium to the maximum concentration of 2.5 × 10¹⁹ cm^–3. In this case, the resistance of the ohmic contacts proves to be less than 5 × 10^–8 Оhm cm², simultaneously with the improvement of the semiconductor’s surface morphology.