The capability of silicon carbide in general to operate at high temperatures, and the fact that the electron mobility of the 4H-SiC polytype is twice that of the 6H polytype, has led to significant interest in 4H-SiC devices. Experimental data for Al/4H-SiC Schottky diodes is limited, and in this article we present forward and reverse I-V characteristics measured over a temperature range of 298-378 K. An analysis of the results shows that the charge transport mechanism is dominated by thermionic emission at forward biases-less than 0.3 V, and series resistance at forward biases greater than 0.9 V. However, for a forward bias in the range of 0.3-0.9 V, we found the data fitted the space-charge-limited emission model. The competing mechanisms of thermionic emission and space-charge-limited emission lead' to nonideal I-V characteristics, resulting in an increase in measured ideality factor. Space-charge-limited currents are dependent on the trap distribution in the material, and the estimated trap density is 4.4 x 10(15) cm(-3) eV(-1). In the reverse direction, the I-V curves follow Bardeen's model for metal-semiconductor contacts with an interfacial layer. Comparison with results published on 6H-SiC Schottky devices shows no significant differences, and our data falls within the spread found in the literature for all SiC results. (C) 2003 American Vacuum Society. [DOI: 10.1116/1.1560249].