Contact structures having I shapes and L shapes, and methods of fabricating I-shaped and L-shaped contact structures, are employed in semiconductor devices and, in certain instances, phase-change nonvolatile memory devices. The I-shaped and L-shaped contact structures produced by these methods exhibit relatively small active areas. The methods that determine the contact structure dimensions employ conventional semiconductor deposit and etch processing steps that are capable of creating readily reproducible results.
Methods of fabricating a phase change memory device having a small area of contact are provided. The method includes forming a lower interlayer insulating layer on a semiconductor substrate, and forming a lower conductor pattern within the lower inter-insulating layer. A first insulating layer pattern which crosses a top surface of the lower conductor pattern is formed on the semiconductor substrate having the lower conductor pattern. A conductive spacer pattern electrically connected to the lower conductor pattern is formed on a sidewall of the first insulating layer pattern. A first interlayer insulating layer is formed on the semiconductor substrate having the conductive spacer pattern. The first interlayer insulating layer and the conductive spacer pattern are planarized to form a bottom electrode. A second insulating layer pattern which crosses a top surface of the bottom electrode and exposes a portion of the bottom electrode is formed on the semiconductor substrate having the bottom electrode. A phase change material spacer electrically connected to the bottom electrode is formed on a sidewall of the second insulating layer pattern. A second interlayer insulating layer is formed on the semiconductor substrate having the phase change material spacer. The second interlayer insulating layer and the phase change material spacer are planarized to form a phase change material pattern.
