Method for manufacturing an asymetric non-volatile memory

A method for manufacturing a non-volatile memory comprising the steps of:

• (i) forming a floating gate on a semiconductor substrate having a first insulating film;
• (ii) implanting impurity ions to an area adjacent to one side of the floating gate while masking at least an area adjacent to another side of the floating gate;
• (iii) forming a second insulating film on the semiconductor substrate including the floating gate, followed by depositing a conductive film on the entire surface of the second insulating film, the conductive film including an upright portion and a horizontally extending portion, the height of the upright portion of the conductive film at a sidewall of the floating gate being greater than the height of the horizontally extending portion of the conductive film,
• (iv) implanting impurity ions into the semiconductor substrate via the conductive film to form an offset region located between the floating gate and one of source/drain regions and underneath the upright portion of the conductive film and source/drain regions located underneath the horizontally extending portion of the conductive film;
• and
• (v) patterning the conductive film to constitute a control gate.