Effect of thermal annealing on Co/n-LEC GaAs (Te) Schottky contacts

The Co/n-GaAs(Te) Schottky barrier diodes have been annealed at temperature s from 100 to 300 degrees C for 5 min and from 350 to 800 degrees C for 1 m in in N-2 atmosphere. Some expressions have been obtained to interpret the relation between the experiment barrier height Phi(b,o) and equilibrium int erface charge density Q(ss)(0) depending on annealing temperature. The Phi( b,o) value has increased and Q(ss)(0) is decreased with increasing annealin g temperature up to 550 degrees C. This increase in the barrier height has been attributed to the value of positive Q(ss)(0), which is responsible for the Fermi level pinning. The relation between the Phi(b,o), and Q(ss)(0) d epending on annealing temperature is in very good agreement with that of th e interface state density distribution especially in the mid-gap. (C) 2000 Elsevier Science Ltd. All rights reserved.