Abstract:
A copper diffusion plug 21 is provided within a pore in dielectric layer (18, 20, 28, 30) over a copper signal line (16). By positioning the plug (21) below a chalcogenide region (36), the plug is effective to block copper diffusion upwardly into the pore and into the chalcogenide region and thus to avoid adversely affecting the electrical characteristics of the chalcogenide region.
Abstract:
A ring shaped heater (26) surrounds a chalcogenide region (36) along the length of a cylindrical solid phase portion (35) thereof defining a change phase memory element. The chalcogenide region (36) is formed in a sub-lithographic pore (34), so that a relatively compact structure is achieved. Furthermore, the ring contact between the heater and the cylindrical solid phase portion (35) results in a more gradual transition of resistance versus programming current, enabling multilevel memories to be formed.