Patent ID: 7851776
Filing Date: 2010-12-14
Classification: H01L

Abstract:
1. A phase change RAM device comprising: an insulating layer formed over a semiconductor substrate and including a conductive plug formed therein; an oxide layer formed over the insulating layer; a pad-type bottom electrode formed in the oxide layer and in contact with the conductive plug, wherein the pad-type bottom electrode has a height substantially equal to a height of the oxide layer; a masking pattern formed over the bottom electrode so as to shield a center part of the pad-type bottom electrode and expose only a peripheral portion of the pad-type bottom electrode, such that a bottom surface of the masking pattern is above an upper surface of the oxide layer; a phase change layer formed directly over the oxide layer and covering a top surface and a side surface of the masking pattern, so as to completely shield the masking pattern, and covering an entire exposed peripheral portion of the bottom electrode; and a top electrode formed on and abutting the phase change layer.