investigation of postannealing effect on efficient ohmic contact to zno thin film using ti/al metallization strategy

Ohmic and schottky contacts are playing a major role in the field of zno based electronics device fabrication.it is seen that several works have been reported on metallization scheme, contacts with this semiconductingmaterial. but, the thickness of semiconducting material and the choosing of substrate still remain imperfectand inefficient for advanced ic technology. to estimate contact resistance, the transmission line method(tlm) is found to be more complex. so, schottky barrier height (sbh) model is considered to obtain atmost accuracy to find ohmic contact parameters. herein, the investigation of parameters like barrier height,ideality factor and saturation current at room temperature of very low specific resistance ohmic contactto zno using ti/al metallization scheme are performed. the thermal evaporation technique is performedfor the deposition of zno thin film of 200 nm and ti (100nm) /al (100nm). further, using a vacuumfurnace, post-annealing treatment is also done at different temperatures (four samples of 300 °c, 450 °c,600 °c and 700 °c at a time period of 20 minutes for each temperature). characterization of the contacts aredone through current-voltage (i –v) using a semiconductor parameter analyzer. the parameters like barrierheight, ideality factor and saturation current of this metallization scheme are extracted from the currentvoltageplot. it is considered that the theory of thermionic emission is the fundamental phenomenon behindcarrier transport at the interface. after post annealing, a comparative analysis is done and the deviations inthe parameters are analyzed from semi-log current versus voltage plot and richardson plot.