Electrical resistivity of thin epitaxial NiAl buried in (Al,Ga)As

We present the first measurements of electrical resistivity for NiAl layers in (Al,Ga)As/NiAl/(Al,Ga)As semiconductor/metal/semiconductor monocrystalline heterostructures. Layer thicknesses in the range 1.5–100 nm have been studied and all were found to be electrically continuous. Four separate components of resistivity are identified and discussed. The room-temperature resistivity is dominated by electron-phonon and interface-roughness scattering. For films 3 nm in thickness and above, the composition of the NiAl compound can be inferred from the phonon resistivity, while the residual resistivity yields the probability of specular reflection from the interfaces. This parameter is approximately 20% for the films studied.