Monolithic integrated device of PIN diode and field effect transistor and method of manufacturing the same

A novel integrated arrangement of a PIN diode and a FET has (a) a HFET or MESFET as the FET; (b) a PIN diode formed of an undoped semiconductor layer with lateral P, I and N regions; and (c) a quasi-planar arrangement of the PIN diode and FET with the undoped semiconductor layer of the diode forming a component of the FET structure. Also claimed is a process for prodn. of the above arrangement, in which (i) the semiconductor layers (2-6) are grown on a semi-insulating substrate (1) by a single epitaxial process; (ii) the semiconductor layers (4, 5, 6) are removed in the region of the PIN diode; (iii) a dielectric layer (7) is applied onto the surface of the arrangement and is structured to form a mask for prodn. of the N and P contact regions of the PIN diode; (iv) the N and P contact regions (8, 9) are implanted in the layer (3) and then a healing process is carried out; and (v) the contacts for the PIN diode and the FET are produced and at least the ohmic contacts for the n-conducting contact region (11) of the PIN diode are applied simultaneously with the ohmic source and drain contacts (12, 14).