Demonstration of Ytterbium-Based Non-Alloyed Ohmic Contacts to n-GaN

Fabrication of electric contacts is one of the most important stages in the electronic devices manufacturing process. Recently, considerable attention is paid to non-alloyed ohmic contact studies, although the more conventional approach usually involves contact formation by rapid thermal annealing of the sputtered metallization. In this work the contact resistance of alloyed (Ti/Al/Ni/Au and Ti/Al) and non-alloyed (Yb/Au) ohmic contacts to n-GaN epitaxial films is compared. Ti/Al/Ni/Au alloyed ohmic contacts have the lowest resistance. However, it is found that the contact resistance values for non-alloyed Yb/Au and alloyed Ti/Al contacts are similar. Thus, low-resistance non-alloyed Yb/Au-based ohmic contacts to n-GaN are demonstrated.