We report on the preparation and characterization of two materials based on cubic NiSi2 (CaF2
-type, cF12, Fmm)
that show no lattice mismatch to Si and are thus promising materials for perfect epitaxial films grown on silicon. The perfectly lattice-matched materials are special compositions within the extended solid solution phases NiSi2−xAlx
with x = 0.26
for Al and x = 0.17
for Ga, respectively. The variations of bulk lattice parameters with the composition were studied by means of x-ray diffraction and the melting behavior of the solid solution phases was investigated by differential thermal analysis. Both phases are thermally stable up to temperatures around 1000 °C.
Phase diagram investigations show that the respective phases are in thermodynamic equilibrium with pure silicon. The electrical conductivity of NiSi2−xAlx
was studied on selected bulk samples between 4.2 and 300 K. Both materials show metallic behavior with specific room-temperature resistivities between 23 and 40 μΩ cm. The difference is mainly due to intrinsic defects in these compounds. © 2003 American Institute of Physics.