Phase changeable memory cells

摘要

A phase changeable memory cell includes a lower interlayer dielectric layer formed on a semiconductor substrate 251 and a lower conductive plug 259 passing through the lower interlayer dielectric layer. The conductive plug is in contact with a phase change material pattern. In one embodiment a lower electrode 261 is disposed on the lower interlayer dielectric layer and a molding layer 263 covers the lower electrode and the lower interlayer dielectric layer. The phase change material pattern 265 is formed on the molding layer and is in contact with the lower electrode through a contact hole 263h that penetrates the molding layer. In another embodiment (fig 2A) the phase change material pattern is disposed on the lower interlayer dielectric layer. In both cases the phase change material pattern and the lower interlayer dielectric layer are covered with an upper interlayer dielectric layer 267. The phase change material pattern is in electrical contact with a plate line 273, via a plate line contact hole 267h passing through the upper interlayer dielectric layer. An active region may be defined in the substrate by an isolation layer, the active region including switching transistors electrically connected to the lower conductive plug. Methods of fabricating the devices are disclosed.