Annular, linear, and point contact structures are described which exhibit a greatly reduced susceptibility to process deviations caused by lithographic and deposition variations than does a conventional circular contact plug. In one embodiment, a standard conductive material such as carbon or titanium nitride is used to form the contact. In an alternative embodiment, a memory material itself is used to form the contact. These contact structures may be made by various processes, including chemical mechanical planarization and facet etching.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 09/809,561, filed on Mar. 15, 2001, which issued as U.S. Pat. No. 6,563,156 on May. 13, 2003, and which has been allowed for reissue as U.S. application Ser. No. 11/008,755. U.S. Pat. No. 6,563,156 is a continuation-in-part of U.S. Ser. No. 09/617,297, filed on Jul. 14, 2000, which issued as U.S. Pat. No. 6,440,837 on Aug. 27, 2002. Both of these patents are herein included by reference in their entirety.
