TEMPERATURE-DEPENDENCE OF IV AND C-V CHARACTERISTICS OF NI/N-CDF2 SCHOTTKY-BARRIER TYPE DIODES

Current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed in the temperature range 45-330 K on Ni/n-CdF2 Schottky barrier type diodes fabricated on unpolished CdF2 surface, etched with 1 : HCl. The diodes showed an MIS structure with interface states and deep donor bulk defects. Under forward bias and for T ≥ 280 K, the electric current transport was controlled by the thermionic emission process. However, for T ≤ 280 K, the current was controlled by thermionic field emission. The zero bias and zero temperature barrier height, φ0 = (0.67 ± 0.07) V was obtained from the I-V measurements and agreed very well with the value of φ0 = (0.60 ± 0.06) V, determined from the C-V data. The energy density of interface states estimated from the room temperature I-V measurements was ≈ 1012 cm-2 eV-1. The interface states were responsible for the non-ideal behavior of the forward I-V characteristics of the diodes. However, the non-linearity in the C-2 vs V curves under reverse bias was introduced by the deep donor levels. From the C-V measurements under reverse bias, two deep levels with energies of EC - (0.7 ± 0.1) eV and EC - (1.0 ± 0.1) eV were detected. © 1990.