Fabrication of Over-Damped Josephson Junctions With ${\rm MgB}_{2}/{\rm Al/AlN/MgB}_{2}$ Structures

MgB
₂
/Al/AlN/MgB
₂
Josephson junctions were fabricated on c-plane sapphire substrates. The current-voltage characteristics of the junctions were over-damped characteristics without any excess current. The critical current was ideally modulated by applying an external magnetic field. By the evaluation of the junction uniformity of 11- and 101-arrayed junctions, 1sigma values of 7.9% and 10.2% were obtained. For parallel junctions, clear current modulations were observed on applying a magnetic field.