The excitonic superconductor proposed by Allender, Bray and Bardeen is a kind of Layered Ultrathin Coherent Structure (LUCS) composed of metal and semiconductor layers. In a previous work, we have studied the electronic structure of a metalme-tal LUCS in the tight binding approximation. We present here the result of a similar study of a metal-semiconductor LUCS, with the hope that it may be helpful to more detailed further investigations of the ABB model of superconductivity.