Semiconductor integrated circuits including grating coupler for optical communication and methods of forming the same

A semiconductor integrated circuit comprising:

• a cladding layer disposed on a semiconductor substrate;
• a grating coupler including an optical waveguide on the cladding layer and a grating on the optical waveguide;
• and
• at least one reflector formed in the semiconductor substrate below the grating and including a reflective surface non-parallel to the top surface of the semiconductor substrate.

A method of forming a semiconductor integrated circuit, the method comprising:

• preparing a substrate including a semiconductor substrate, a cladding layer, and a semiconductor layer, which are sequentially stacked;
• forming at least one reflector in the substrate using an element ion implantation process;
• and
• patterning the semiconductor layer to form a grating coupler, the grating coupler including an optical waveguide on the cladding layer and a grating on the optical waveguide,
• wherein the reflector is formed below the grating.

A method of forming a semiconductor integrated circuit, the method comprising:

• preparing a substrate including a semiconductor substrate, a cladding layer, and a semiconductor layer, which are sequentially stacked;
• forming compound patterns on an upper portion of the semiconductor layer using an ion implantation process, the compound patterns being laterally spaced apart from each other and having oblique both sidewalls;
• and
• patterning the semiconductor layer to form a grating coupler, the grating coupler including an optical waveguide on the cladding layer and a grating on the optical waveguide,
• wherein a protruding portion of the grating is a portion of the semiconductor layer between the compound patterns.