ABSTRACT

DOEs can be fabricated on silicon substrates through plasma-chemical etching. But this technique produces trenches whose profiles and depths deviate from the design intent [236]. Reference 298 proposes a patented technique for fabricating DOE microreliefs that involves coating a substrate with a catalytic mask. Once the mask is deposited, the structure is heated in a carrier gas by using a large-aperture irradiation flux with a wavelength within the transmission window of the material being treated. In this case, the catalytic mask determines the geometry of microrelief trenches.