Preparation of high quality all‐refractory Josephson tunnel junctions based on Nb/Al‐oxide‐Nb and Nb/Al‐oxide‐Al/Nb structures is reported. Critical currents up to 1300 A/cm2andVmvalues up to 35 mV were obtained. The specific capacitance of these junctions is 0.06±0.02 pF/&mgr;m2. Junctions were fabricated using standard photolithography and a new plasma etching process coupled with anodization of Nb.