A new approach is presented for the development of a metal‐insulator–semiconductor field‐effect transistor technology. It is applied to the optimization of Al2O3/InP structures prepared by the deposition of evaporated Al2O3on arsenic‐stabilized InP surfaces. Molecular beam epitaxy and surface‐science techniques (reflected high‐energy electron diffraction and x‐ray photoelectron spectroscopy are used to control step by step the fabrication of the structures and to describe the microscopic properties of the interfaces. The optimization of the fabrication process is based on correlations between interfacial physicochemical properties and metal–insulator‐semiconductor capacitor electrical properties. It is shown that an interfacial oxide buffer layer can favor crystallochemical matching between Al2O3and InP.