Substrate for high frequency integrated circuits

A silicon substrate material based on silicon has a semi-insulating interior layer isolating the bulk of the substrate material from the top layers, where integrated circuits are to be built. The semi-insulating layer is created by producing submicron particles having Schotty barriers or pn-hereto-barriers and distributing X particles so that the depletion regions then produced around neighbouring particles overlap. Such particles will then deplete the silicon material from electric charge carriers. The substrate material can then be processed using the standard silicon processing methods and allows integrated circuits to be manufactured which are suitable for high frequency applications. A silicon substrate is made by sputtering a metal such as Co in a silicon wafer and then silicidizing the sputtered Co atoms by means of an annealing treatment. A top silicon wafer having a silicon dioxide layer at its bottom surface is then bonded to the sputted layer. Finally the top wafer is thinned to provide a layer thickness suitable for the processing steps required in the manufacture of components.