  In this paper, we investigate the electrical evolution of tungsten (W) and
tungsten carbide (WC) Schottky contacts on 4H-SiC subjected to thermal
treatments at different annealing temperatures from 475 to 700 {\deg} C. For
each annealing temperature, the uniformity of the Schottky barrier height
(${\phi_B}$) and ideality factor (n) was monitored by current-voltage (I-V)
measurements in forward bias, performed over sets of equivalent diodes. Good
values of n (below 1.05) were found for both contacts up to thermal annealing
at 700 {\deg} C. On the other hand, the barrier of the two contacts behaves
differently. For the W/4H-SiC diode, the ${\phi_B}$ increases with the
annealing temperature (from 1.14 eV at 475 {\deg} C to 1.25 eV at 700 {\deg}
C), whereas the Schottky barrier in WC/4H-SiC features a slight reduction
already with thermal annealing at 475 {\deg} C, remaining almost constant at
around 1.06 eV up to annealing at 700 {\deg} C. A deeper characterization was
performed on the 700 {\deg} C-annealed contacts by studying the
temperature-dependence of the Schottky parameters by
current-voltage-temperature (I-V-T) characterization. The ${\phi_B}$ and n
behaviour with temperature indicates the presence of a nanoscale lateral
inhomogeneity for both Schottky contacts, which can be described by Tung's
model. Finally, the temperature-dependence of the reverse characteristics could
be described by the thermionic field emission model (TFE), accounting for the
temperature dependent barrier height determined from forward characterization.
