Patent ID: 8860174

Claim:
A recessed access device antifuse, comprising: a trench in a semiconductor substrate and comprising: an upper portion comprising opposing vertical sidewalls; and an at least partially spherically shaped bottom portion extending beyond lateral boundaries of the upper portion of the trench; a bottom portion comprising at least one curved surface; an insulative material lining the trench; a first material in the trench and isolated from the semiconductor substrate by the insulative material, a portion of the first material extending below a surface of the semiconductor substrate and another portion of the first material extending above the surface of the semiconductor substrate; material; a second material in the trench and in contact with the insulative material and the first material in the trench, the second material confined within lateral boundaries of at least one of the upper portion and the at least partially spherically shaped bottom portion of the trench and electrically isolated from the semiconductor substrate by at least one of the insulative material and the first material, a portion of the second material extending below the surface of the semiconductor substrate and another portion of the second material extending above the surface of the semiconductor substrate, a work function value of the second material higher than a work function value of the first material; and an antifuse breakdown area in the insulative material, adjacent to a boundary between the first material and the second material.