Schottky diode formation and characterization of titanium tungsten to n- and p-type 4H silicon carbide

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Abstract
Titanium tungsten (Ti0.58W0.42) Schottky contacts to both n- and p-type 4H silicon carbide were fabricated using sputtering. The n- as well as p-type Schottky contacts had excellent rectifying characteristics after vacuum annealing at 500 °C with a thermally stable ideality factor of 1.06±0.03 for n-type and 1.08±0.01 for p-type. The measured Schottky barrier height (SBH) was 1.22±0.03 eV for n-type and 1.93±0.01 eV for p-type in the range of 24–300 °C. Our results of Ti0.58W0.42 Schottky contacts to both n- and p-type can be explained perfectly by thermionic emission theory and also satisfy the Schottky–Mott model in contrast to earlier works. Capacitance–voltage measurements were also performed and the results were in good agreement with those of current–voltage measurements. In addition, the inhomogeneous behavior with higher ideality factor and lower SBH of p-type Ti0.58W0.42 contacts for as-deposited contacts is explained by using a model with contribution of recombination current originated by lattice defects to thermionic emission current.