Abstract: A method for the heat treatment of oxygenated and lightly doped silicon single crystals provides a conductive silicon substrate which draws off stray currents from adjacent n-channel and p-channel transistors, preventing latch-up in CMOS integrated circuits. A lightly doped oxygenated, single crystal silicon wafer is heated at 1000.degree. to 1150.degree. C. to out-diffuse oxygen from the surface layer. After device fabrication on this denuded surface, the wafer is heated at 450.degree. C. to generate oxygen donors in the bulk of the wafer which then becomes strongly conductive or n-type. The wafer surface will remain lightly doped, either n-- or p-type from the original doping. By suitable masking during the oxygen out-diffusion step, islands of lightly doped p-- or n-type material on the surface may be surrounded by guard rings of strongly conducting n-type material formed in the final heating step at 450.degree. C.

Abstract: A method for making semiconductor integrated circuits which improves and decreases fringing capacitance in semiconductor integrated circuits. An oxygenated, single-crystal silicon lamella is lightly doped, producing an excess of holes, thereby forming a semiconductor substrate. The substrate is used to fabricate semiconductor devices in the usual way, except that density may be slightly increased. After fabrication, the substrate is heated, preferably at 450.degree. C., until resistivity of the substrate has increased so that non-diffused regions of the substrate are substantially non-conductive.