Fabrication process of a microfabricated blazed grating

A process for fabricating a blazed grating of the microfabricated type from an SOI substrate comprising a silicon lower layer surmounted by a silicon oxide buried layer, itself surmounted by a silicon upper layer, comprising the steps of:

• a) carrying out a dry etching down to said silicon oxide layer through a first photolithography operation in order to define a first protective mask before the silicon upper layer is dry-etched down to the silicon oxide layer in order to form trenches defining parallel beams and arms connecting said beams in pairs;
• b) defining a second protective mask;
• c) carrying out a lithography operation so as to obtain an asymmetric protection of only one of the two sides of each of said beams along a direction perpendicular to the beam direction;
• d) carrying out a chemical or plasma etching so as to remove said second protective mask;
• e) carrying out an anisotropic chemical etching of said silicon upper layer in order to form an inclined reflection surface on each of said beams;
• and
• f) carrying out an acid etch in order to remove at least the silicon oxide portions located beneath said beams and beneath said arms, with the exception of predefined anchoring zones, and to form a suspended grating.