Novitskii S. Cathode contacts with TiBx diffusion barriers for indium phosphide Gunn diodes

The thesis deals with investigation of physical processes in multilayer ohmic contacts to n-InP with TiBx diffusion barrier subjected to external actions, such as microwave irradiation, rapid thermal annealing (RTA) and ^60Со gamma-irradiation. It was found that Au-TiBx-Ge-Au-n-n+-n++-InP ohmic contacts formed using magnetron sputtering followed by RTA at a temperature of 450 °С retain their structure and contact resistivity value at Gunn diode operating temperatures. The contacts subjected to RTA at T = 400 °С followed by ^60Со gamma-irradiation up to a dose of 10^7 Gy demonstrated degradation processes caused by oxygen diffusion through the TiBx film. For the first time, a growing temperature dependence of contact resistivity was obtained for Au-Ge-TiBx-Au ohmic contact to n-n+-n++-InP in the 80-380 K temperature range. This was explained by current flow through metal shunts associated with dislocations that short-circuit space-charge region, with allowance made for current limitation by diffusion supply of electrons.