Barrier height homogeneity for 4.5 kV 4H-SiC Schottky diodes

4.5 kV SiC Schottky diodes have been fabricated using Ni as the Schottky contact. A manufacturing yield of 40% is reached for the bigger area diodes (1.6×1.6 mm2) and of 70% for the smaller ones (0.4×0.4 mm2). The measured variations of barrier height and ideality factor with temperature do not agree with the thermionic model. This has been interpreted in terms of barrier height inhomogeneities using the Werner model. We extracted an average barrier height ϕb¯=1eV and its standard deviation (σ=90mV). These two parameters are almost independent of the diode size. The variation of the barrier height distribution with field has also been investigated and shows a dependence similar to that of Schottky diodes realized from other semiconductor materials.