Temperature-dependent I-V characteristics in thermally annealed Co/p-InP contacts

Abstract

We prepared the sputtered Co/p-InP Schottky diodes which consisted of as-deposited, and diodes annealed from 200 °C to 700 °C. The annealed samples were cooled from the annealing temperature down to room temperature, and then, their current-voltage (I-V) characteristics were measured. Schottky barrier height (SBH) at 300 K slightly decreases from 0.80 eV (for as-deposited sample) down to 0.77 eV (for the sample annealed at 400 °C) with the annealing temperature and then again increases up to 0.91 eV for the sample annealed at 700 °C. The I-V measurements were made in the sample temperature range of 60-400 K. It is seen that the SBH for each diode monotonically increases with increasing the sample temperature up to 400 K. In the sample temperature range of 60-400 K, the Co/p-InP SBD annealed at 400 °C has a lower ideality factor value than those of the as-deposited and 200 °C annealed SBDs at each sample temperature. Thus, remarkable apparent improvement of the diode parameters has been achieved by means of the thermal annealing. The improvement in the Co/p-InP interface due to the thermal annealing process has continued without deteriorating at each measurement temperature from 60 K to 400 K. Therefore, it has been concluded that the thermal annealing process translates the MS Schottky contacts into thermally more stable Schottky contacts. © 2011 EDP Sciences.