INTEGRATED CIRCUITS COMPRISING LATERAL TRANSISTORS AND PROCESS FOR FABRICATION THEREOF

A "lateral" transistor for use in integrated circuits may have its base region formed by a technique of "ion implantation" with or without a step of impurity diffusion or, alternatively, by two steps of impurity diffusion including the formation of the so-called "buried" layer. In either case an emitter region is double-diffused into the base region simultaneously with collector diffusion, in such a manner that the base width of the lateral transistor is defined by a difference between the lengths of the double diffusion. The aforesaid ion implantation and buried layer techniques are utilized in the fabrication of integrated circuits incorporating such lateral transistors, in which base regions and isolation regions are formed at the same time. In other integrated circuits also disclosed herein, the lateral transistors together with or without field-effect transistors are isolated by means of substrate having higher resistivity than the base regions of the transistors.