Method of depositing optical films
AssigneeDALSA Semiconductor Inc.
InventorsLuc Ouellet, Jonathan Lachance, Manuel Grondin, Stephane Blain
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Abstract
To deposit optical quality films by PECVD (Plasma Enhanced Chemical Vapor Deposition), a six-dimensional space wherein five dimensions thereof correspond to five respective independent variables of which a set of four independent variables relate to the flow-rate of respective gases, a fifth independent variable relates to total pressure, and a six dimension relates to observed FTIR characteristics is first created. Then an optical film is deposited while maintaining three of the set of four independent variables substantially constant as well as the fifth independent variable, and varying a fourth of the set of four independent variables to obtain desired characteristics in the sixth dimension.
Claims19
A method of making silica waveguides, comprising:
- depositing optical films by PECVD (Plasma Enhanced Chemical Vapour Deposition) in the presence of a silicon-containing gas, an oxidation gas, a carrier gas, and PH3 as a doping gas, said optical films having refractive indices differing by an amount delta-n;
- setting a total pressure of said gases and flow rates of said silicon-containing gas, said oxidation gas, and said carrier gas at constant values to minimize absorption peaks in FTIR spectra;
- and
- adjusting the flow rate of said doping gas while maintaining said total pressure and said flow rates at constant values to achieve a target value for said delta-n without changing the FTIR spectra.
A method of making silica waveguides, comprising:
- defining a six-dimensional space wherein five dimensions thereof correspond to first, second, third, fourth, and fifth respective independent variables, of which said first, second, third, and fourth independent variables relate respectively to the flow-rate of a raw material gas, an oxidation gas, a carrier gas, and a doping gas, and said fifth independent variable relates to total pressure, and a sixth dimension relates to observed FTIR characteristics;
- depositing optical quality films having refractive indices differing by an amount delta-n by PECVD (Plasma Enhanced Chemical Vapour Deposition) while maintaining said first, second, third and fifth independent variables constant at values selected to optimized said observed FTIR characteristics;
- and
- varying said fourth independent variable to obtain the desired delta-n without changing said observed FTIR characteristic;
- and
- wherein said doping gas is selected from the group consisting of PH3;
- B2H6;
- AsH3;
- TiH4;
- GeH4;
- SiF4;
- and CF4.
Dependencies are inferred from the claim text.