FORMATION OF THICK SILICON DIOXIDE LAYER ON SILICON SUBSTRATE AND PRODUCTION OF OPTICAL WAVEGUIDE ON SILICON SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a thick SiO2 layer on a Si substrate at a heating temp. lower than the m.p. of Si of the substrate without a high pressure treatment and a method for producing an optical waveguide on the substrate. SOLUTION: The thick SiO2 layer 3 is formed on the Si substrate 1 by making the surface of the Si substrate porous 2 and oxidizing under heating at the temp. lower than the m.p. of the Si. The optical waveguide is produced by using the thick SiO2 layer 3 as an under clad layer, forming a core layer 4 thereon, leaving only a waveguide pattern 4a with the removal of another part and forming an over clad layer 5 on the core layer 4.