PHASE-CHANGE MEMORY DEVICE AND METHOD FOR FORMING THE SAME

摘要

A phase change memory device is provided to prevent an etch stop layer and a silicon nitride layer from being broken by reducing the stress generated at the edge of a semiconductor by a first silicon oxide layer. A semiconductor substrate is prepared which has a conductive region(105) and an isolation region(102). An etch stop layer(120) has an opening exposing the conductive region. A first silicon oxide layer(110) comes in contact with the upper or lower surface of the etch stop layer. A second silicon oxide layer(130) is formed on the etch stop layer. A silicon nitride layer(140) is formed on the second silicon oxide layer. A diode(135) is formed in the opening, coming in contact with the conductive region of the semiconductor substrate. A lower electrode(146) is formed on the diode, connected to the diode. The opening continuously penetrates the first silicon oxide layer, the second silicon oxide layer and the silicon nitride layer. The etch stop layer, the first silicon oxide layer, the second silicon oxide layer and the silicon nitride layer can be positioned on the isolation region.