PRODUCTION OF OPTICAL WAVEGUIDE FILM

摘要

PROBLEM TO BE SOLVED: To obtain a quartz film having little amount of reaction intermediate therein and causing no shrinkage after its annealing by specifying the refractive index of the quartz film immediately after deposited onto a silicon substrate to a specific thickness through a plasma chemical vapor reaction using tetraethoxysilane and oxygen as raw material gases. SOLUTION: This quartz film having a refractive index of 1.47±0.01 immediately after deposited on a silicon substrate to a thickness of >=5μm is obtained by reducing the content of the reaction intermediate carbon in the resultant film to <=5 wt.% by controlling a feed of oxygen within 0.7 to 3.0 times a theoretical amount calculated by using a feed of tetraethoxysilane and/or by setting a high-frequency electric power applied in the plasma chemical vapor reaction to >=100 W, pref. >=200 W. By annealing this quartz film, the objective high quality optical waveguide film freed from any reaction intermediates and having the refractive index within the range of 1.458 to 0.001 is obtained.