Read-only memory cell and method of forming same.

摘要

A read-only memory cell (70) is formed at a face (72) of a semiconductor layer (74) having a first conductivity type. A bit line region (54) is formed in the semiconductor layer (74) to be of a second conductivity type. A bit line conductor (44) is coupled to the bit line region (54). A first voltage source region (84) is formed in the semiconductor layer (74) to be of the second conductivity type and is coupled to a source of a first voltage (Vdd) representative of a first bit value. A first potential channel region (80) is disposed at the face (72) between the bit line region (54) and the first voltage source region (84). A second voltage source region (56) is formed in the semiconductor layer (74) to be of the second conductivity type and is coupled to a source of a second voltage (Vss) representative of a second bit value. A second potential channel region (82) is disposed at the face (72) between the bit line region (54) and the second voltage source region (56). A gate insulator layer (76) is formed on the face (72). A word line conductor (42a) is formed on the gate insulator layer such that a predetermined voltage thereon will render a preselected one (82) of the potential channel regions (80, 82) conductive. A thick insulator layer (77) deselects the non-selected potential channel region (80) and prevents the formation of a transistor thereacross.