Electro optical devices fabricated using deep ultraviolet radiation

A method of providing an optical device, comprising:

• providing a hard mask layer on a ferroelectric nonlinear optical layer, the ferroelectric nonlinear optical layer including at least one ferroelectric nonlinear optical material;
• providing a mask on the hard mask layer, the mask having a pattern formed using ultraviolet (UV) lithography;
• forming a hard mask from the hard mask layer by transferring the pattern to the hard mask layer, the forming including performing a first etch for removing a portion of the hard mask layer to form the hard mask;
• and
• transferring the pattern from the hard mask to the ferroelectric nonlinear optical layer to form at least a portion of the optical device including a sidewall of the at least one ferroelectric nonlinear optical layer, the transferring the pattern including performing a second etch for removing a portion of the at least one ferroelectric nonlinear optical layer to form the sidewall, the second etch being selected from a dry etch, a reactive ion etch (RIE), a plasma etch and a chemical etch, the second etch being different from the first etch such that the sidewall has a short range root mean square roughness of less than ten nanometers.

A method for providing an optical device, comprising:

• providing a hard mask layer on a ferroelectric nonlinear optical layer, the ferroelectric nonlinear optical layer including at least one ferroelectric nonlinear optical material;
• providing a mask on the hard mask layer, the mask having a pattern formed using deep ultraviolet (DUV) lithography, the providing the mask further including
• providing a mask layer;
• heat treating the mask layer at a first temperature of greater than 140 degrees Celsius, the heat treating including increasing a temperature for the mask layer at a rate of not more than 140 degrees Celsius per minute;
• exposing portions of the mask layer using electromagnetic radiation in a DUV wavelength range;
• performing an additional heat treating after the exposing at a second temperature of greater than one hundred forty degrees Celsius, the additional heat treating including increasing an additional temperature for the mask layer at an additional rate of not more than 140 degrees Celsius per minute;
• developing the mask layer after the additional heat treating to form at least one aperture in the mask layer corresponding to the pattern and form the mask;
• forming a hard mask from the hard mask layer by transferring the pattern to the hard mask layer using a hard mask etching;
• and
• etching the ferroelectric nonlinear optical layer to transfer the pattern from the hard mask to the ferroelectric nonlinear optical layer and form a sidewall therein, the etching being selected from dry etching, reactive ion etching (RIE), plasma etching and chemical etching, the etching being different from the hard mask etching such that the sidewall has the short range root mean square roughness of less than ten nanometers.