The present invention relates to a structure of the insulator--semiconductor type in which the semiconductor is a III-V compound and to processes for the production of said structure. It can be used on the one hand in microelectronics where it permits the production of high performance (speed, degree of integration, etc) components of the MIS type (metal--insulator--semiconductor) and on the other hand in optoelectronics where it permits the passivation of the surfaces of optoelectronic components, e.g. semiconducting lasers.
For some years now, an increasing importance and interest has been attached to composite semiconductors of the III-V type (e.g. GaAs or InP). These materials have in fact remarkable properties making them particularly suitable for the construction of integrated electronic components of the MIS type, where they lead to a considerable improvement in performance figures compared with conventional components based on silicon and germanium. Among these properties, particular reference is made to the high electronic mobility (approximately 10,000 cm/s for the GaAs and 5,000 for InP, as compared with only 1,200 for Si and 3,600 for Ge), the forbidden band width (approximately 1.4 eV compared with 1.1 eV for Si and 0.7 eV for Ge) and the high resistivity (approximately 10.sup.6 .OMEGA.cm).
However, hitherto the hopes set on III-V compounds have not been crowned with success due more particularly to the fact that it has proved very difficult to make a suitable interface between the insulator and the semiconductor. Attempts have been made to deposit insulators such as SiO.sub.2, Al.sub.2 O.sub.3, Si.sub.3 N.sub.4, Ge.sub.2 N, GaN, etc . . . , but the electrical characteristics (current--voltage, capacitance--voltage, interface charges) obtained for these insulator--semiconductor interfaces do not provide the necessary high quality for the construction of MIS components.