Self-aligned patterning with implantation

A method of fabricating a plurality of features, the method comprising:

• providing a dielectric layer over a silicon layer;
• etching the dielectric layer and the silicon layer to form a plurality of first apertures in the dielectric layer and the silicon layer, wherein adjacent apertures of the plurality of first apertures are set apart by a first pitch;
• etching a plurality of second apertures in the dielectric layer, each aperture of the plurality of second apertures having a greater width than and centered about a respective aperture of the plurality of first apertures;
• implanting a first plurality of dopants into the silicon layer aligned through the plurality of second apertures in the dielectric layer;
• etching a plurality of third apertures in the dielectric layer, each aperture of the plurality of third apertures having a greater width than and centered about a respective aperture of the plurality of second apertures;
• providing a patterning film over the silicon layer through the plurality of third apertures in the dielectric layer;
• removing the dielectric layer to expose a portion of the silicon layer through the patterning film;
• implanting a second plurality of dopants into the exposed silicon layer through the patterning film, wherein doped portions of the silicon layer are set apart by a second pitch less than the first pitch;
• and
• removing undoped portions of the silicon layer.

A method of fabricating a plurality of features, the method comprising:

• providing a dielectric layer over a silicon layer;
• etching the dielectric layer and the silicon layer to form a plurality of first apertures in the dielectric layer and the silicon layer, wherein adjacent apertures of the plurality of first apertures are set apart by a first pitch;
• etching a plurality of second apertures in the dielectric layer, each aperture of the plurality of second apertures having a greater width than and centered about a respective aperture of the plurality of first apertures;
• implanting a first plurality of dopants into the silicon layer aligned through the plurality of second apertures in the dielectric layer;
• etching a plurality of third apertures in the dielectric layer, each aperture of the plurality of third apertures having a greater width than and centered about a respective aperture of the plurality of second apertures;
• providing a patterning film over the silicon layer through the plurality of third apertures in the dielectric layer;
• removing the dielectric layer to expose a portion of the silicon layer through the patterning film;
• implanting a second plurality of dopants into the exposed silicon layer through the patterning film, wherein doped portions of the silicon layer are set apart by a second pitch which is one third of the first pitch;
• removing the patterning film;
• and
• removing undoped portions of the silicon layer.