Schottky contacts of Al/Si1−x−yGexCywere fabricated using conventional Si technology. Effects of thermal processing of the alloys on the electrical properties of the Al/Si1−x−yGexCySchottky diodes were investigated. Current–voltage (I–V), capacitance–voltage (C–V), and x‐ray diffraction measurements were performed. These thick alloy films (100–150 nm) experienced strain relaxation upon annealing at 700 °C. Nearly idealI–VandC–Vbehaviors were obtained for strain‐compensated samples.I–VandC–Vcharacteristics show evidence of dislocation‐related traps for strain‐relaxed samples. Carbon incorporation improves theI–VandC–Vcharacteristics by lessening the extent of lattice relaxation due to thermal processing. ©1996 American Institute of Physics.