Method for making a conductive silicon substrate by heat treatment of oxygenated and lightly doped silicon single crystals

A method for making a conductive silicon substrate for semiconductor devices comprising,

• (a) forming an oxygenated, doped, single-crystal silicon wafer substrate, having opposite major surfaces and having semiconductor electrical conductivity,
• (b) depleting the surface of said substrate of oxygen by heating the substrate at a temperature between 1,000.degree.-1,150.degree. C. for a length of time sufficient to obtain the desired depth of oxygen-depleted surface layer,
• (c) fabricating semiconductor devices on one of the substrate surfaces by planar processing, and then
• (d) forming oxygen donors in the substrate bulk by heating the substrate to a temperature of about 450.degree. C. until the substrate bulk becomes highly conductive and a semiconductor electrical conductivity type junction occurs at the interface between an oxygen-depleted surface layer and the bulk of the substrate.

A method for making a conductive substrate for semiconductor devices comprising,

• (a) forming an oxygenated, doped single-crystal silicon wafer substrate, having opposite major surfaces and having semiconductor electrical conductivity,
• (b) heating the substrate at a temperature between 1,000.degree.-1,150.degree. C. to deplete the substrate surfaces of oxygen,
• (c) fabricating semiconductor devices on one of the substrate surfaces by planar processing, and then
• (d) heating the substrate to a temperature in the range of between 500.degree.-800.degree. C. until the bulk of the substrate between the surfaces becomes highly conductive.