AN ION-ASSISTED DEPOSITION SYSTEM FOR USE IN THE FABRICATION OF SUBMICRON DIMENSION DEVICE OHMIC CONTACTS

The design and characterisation of a novel ion-assisted deposition sys tem for use in the fabrication of ohmic contacts to submicron dimensio n devices is described. The system is based on a conventional electron beam evaporator, which was modified to simultaneously evaporate and p artly ionise the contact metallisation. The substrate holder is biased in order that the deposition of the contact metallisation upon the su bstrate occurs under the influence of low energy ion bombardment. Esti mated ionisation efficiencies as high as 7% and ion doses of 5 X 10(15 ) ions cm(-2) have been obtained using Ge as the source material.