Abstract: Disclosed are a phase change RAM device and a method for fabricating a phase change RAM device, which can efficiently lower intensity of current required for changing a phase of a phase change layer. The method includes the steps of providing a semiconductor substrate formed with an insulating interlayer including a tungsten plug, forming a first oxide layer on the semiconductor substrate, forming a pad-type bottom electrode, which makes contact with the tungsten plug, in the first oxide layer, forming a second oxide layer on the first oxide layer including the bottom electrode, and forming a porous polystyrene pattern on the second oxide layer such that a predetermined portion of the second oxide layer corresponding to a center portion of the bottom electrode is covered with the porous polystyrene pattern.

Abstract: A phase change memory device includes a silicon substrate having cell and peripheral regions. A first insulation layer with a plurality of holes is formed in the cell region. Recessed cell switching elements are formed in the holes. Heat sinks are formed in the holes in which the cell switching elements are formed, and the heat sinks project out of the first insulation layer. A gate is formed in the peripheral region and has a stack structure of a gate insulation layer, a first gate conductive layer, a second gate conductive layer, and a hard mask layer. A second insulation layer is formed on the surface of the silicon substrate. The second insulation layer has contact holes exposing the heat sinks. Heaters are formed in the contact holes, and stack patterns of a phase change layer and a top electrode are formed on the heaters.

Abstract: A phase change memory device reduces the current necessary to cause a phase change of a phase change layer. The phase change memory device includes a first oxide layer formed on a semiconductor substrate; a lower electrode formed inside the first oxide layer; a second oxide layer formed on the first oxide layer including the lower electrode, the second oxide having a hole for exposing a part of the lower electrode; a phase change layer formed on a surface of the hole with a uniform thickness so as to make contact with the lower electrode; and an upper electrode formed in the hole and on a part of the second oxide layer, the part being adjacent to the hole.

Abstract: A phase change memory device resistant to stack pattern collapse is presented. The phase change memory device includes a silicon substrate, switching elements, heaters, stack patterns, bit lines and word lines. The silicon substrate has a plurality of active areas. The switching elements are connected to the active areas. The heaters are connected to the switching elements. The stack patterns are connected to the heaters. The bit lines are connected to the stack patterns. The word lines are connected to the active areas of the silicon substrate.

Abstract: A phase change memory device resistant to stack pattern collapse is presented. The phase change memory device includes a silicon substrate, switching elements, heaters, stack patterns, bit lines and word lines. The silicon substrate has a plurality of active areas. The switching elements are connected to the active areas. The heaters are connected to the switching elements. The stack patterns are connected to the heaters. The bit lines are connected to the stack patterns. The word lines are connected to the active areas of the silicon substrate.

Abstract: A phase change memory device includes a silicon substrate having a phase change cell region. A plurality of phase change cell are formed in the phase change region of the silicon substrate. A contact comprising a first contact and a second contact is formed on each of the phase change cells. A plurality of bit lines are electrically connected to the contacts. A contact plug is formed on the silicon substrate in a region outside of the phase change cell region, and a word line is formed over the silicon substrate and is connected to the contact plug.

Abstract: A phase change memory device having a uniform set and reset current includes a first and second sense amplifiers that are respectively placed adjacent to both ends of a plurality of active regions. The active regions include a first active region and a second active region. The first active region has a first area having a first width, a second area having a second width greater than the first width, and a third area having a third width greater than the second width and are sequentially arranged in a direction extending toward an area adjacent to the first sense amplifier. The second active region has a first area having a first width, a second area having a second width greater than the first width, and a third area having a third width greater than the second width, which are sequentially arranged in a direction extending toward an area adjacent to the second sense amplifier.

Abstract: A contact structure, a method of manufacturing the same, a phase-changeable memory device having the same, and a method of manufacturing the phase-changeable memory device are described. The phase-changeable memory device includes: an upper electrode, a bit line, and a bit line contact unit. The upper electrode is on a semiconductor substrate having a phase-change pattern. The bit line is on the upper electrode. The bit line contact unit is interposed between the upper electrode and the bit line and electrically couples together the upper electrode to the bit line. The bit line contact unit includes a main conductive layer, a first and second barrier film. The first barrier film surrounds a bottom portion and a side portion of the main conductive layer. The second barrier film is on the main conductive layer.

Abstract: A phase-change random access memory (PRAM) is presented which can ensure the integrity of the electrical characteristics of driving transistors even when the PRAM is with a high temperature SEG fabrication process because the fabrication time is minimized. A method of manufacturing the PRAM includes the following steps. After preparing a semiconductor substrate having a cell area and a peripheral area, a junction area is formed in the cell area. Then, a transistor having a gate electrode with a single conductive layer is formed in the peripheral area. Subsequently, a first interlayer dielectric layer is formed at an upper portion of the semiconductor substrate, and then a contact hole is formed by etching the first interlayer dielectric layer to expose a predetermined portion of the junction area. Next, an epitaxial layer is grown in the contact hole.

Abstract: A phase change memory device includes a semiconductor substrate having an active region. An insulation layer is formed on the semiconductor substrate grooves and holes are defined in the insulation layer, with the holes being defined under the grooves to expose portions of the active region. Cell switching are elements formed in the holes and lower portions of the grooves and a phase change layer formed in upper portions of the grooves over the cell switching elements and on portions of the insulation layer adjacent to the grooves such that the phase change layer has a pore structure. Top electrodes are formed on the phase change layer.

Abstract: A phase change memory device includes a semiconductor substrate having bar-shaped active regions which extend in a first direction; base regions and emitter regions alternately formed in each active region; lower electrodes formed over the emitter regions to connect to the respective emitter regions; a phase change layer and an upper electrode stacked on each of the lower electrodes; sub bit lines formed over the upper electrodes to come into contact with the corresponding upper electrodes; word lines arranged over the sub bit lines to come into contact with the base regions; and a main bit line formed over the word line to come into contact with the sub bit lines. The phase change memory device is able to prevent a change in the composition of the phase change layer and additionally is able to widen the sensing margin of a bit line.

Abstract: A phase change memory device includes a semiconductor substrate having an impurity region and an interlayer dielectric applying a tensile stress formed on the semiconductor substrate and having contact holes exposing the impurity region. Switching elements are formed in the contact holes; and sidewall spacers interposed between the switching elements and the interlayer dielectric and formed as a dielectric layer applying a compressive stress.

Abstract: A phase change memory device includes a semiconductor substrate having a plurality of bar-type active areas. A plurality of word lines are arranged in a direction perpendicular to the active areas on the semiconductor substrate, and a first pair of the word lines connected to each other at each first end thereof is arranged alternately with a second pair of the word lines connected to each other at each second end thereof opposite to the first end. Source areas and drain areas are formed in the active areas. Common source areas are each connected to the source areas. A plurality of lower electrodes are connected to the respective drain areas. Phase change layers make contact with every two diagonally adjoining lower electrodes. Upper electrodes are formed on the phase change layers, and bit lines are arranged in a direction of the active areas and are connected to the upper electrodes.

Abstract: A phase change memory device is manufactured by forming a sacrificial layer and a hard mask layer on a lower electrode; performing a first etching these layers and forming on the lower electrode a first stack pattern having a first width less than a width of the lower electrode; performing a second etching the first stack pattern and forming a second stack pattern having a second width less than the first width; forming an insulation to cover the second stack pattern; CMPing the insulation layer to expose the sacrificial layer; removing the sacrificial layer to define a contact hole; forming a lower electrode contact in the contact hole; and forming a phase change layer and an upper electrode on the insulation layer including the lower electrode contact. By manufacturing the phase change memory device in this manner, the size of the contact hole can be decreased and uniformly defined.

Abstract: A phase change memory device is made by processes including forming a first interlayer dielectric on a semiconductor substrate that has junction regions. Then etching the first interlayer dielectric and thereby defining contact holes that expose the junction regions. A conductive layer is formed on the first interlayer dielectric to fill the contact holes. Forming a hard mask layer on the conductive layer and etching the hard mask layer and the conductive layer to form contact plugs in the contact holes. Finally, forming a conductive layer pattern that is located on the contact plug and portions of the first interlayer dielectric adjacent to the contact plug and having a hard mask thereon.

Abstract: A phase change memory device includes a silicon substrate having a cell region and a peripheral region. A first insulation layer is formed in the cell region and includes a plurality of holes. Cell switching elements are formed in the holes of the first insulation layer and heat sinks are formed on the cell switching elements. The heaters are formed on the center of the heat sinks and spacers are formed on the sidewalls. A gate is formed in the peripheral region of the silicon substrate formed of a gate insulation layer, a first conductive layer, a second conductive layer, and a hard mask layer. A second insulation layer covers the entire surface of the resultant silicon substrate and exposes the spacers and the heaters and the hard mask layer. Finally, a stack pattern of a phase change layer and a top electrode is formed on the heaters.

Abstract: A phase change memory device and a corresponding method of manufacturing the same is presented. The phase change memory device includes a silicon substrate, a first insulation layer, cell switching elements, heaters, a gate, a second insulation layer, a barrier layer, a phase change layer and top electrodes. The first insulation layer is in the cell region of the substrate and has a first holes. The cell switching elements are formed in the first holes. The heaters are formed on the cell switching elements. The gate is in the peripheral region of the substrate and is higher than the cell switching elements. The second insulation layer having second holes which expose the heaters, and is defined to expose a hard mask layer of the gate. The barrier layer is on sidewalls of the second holes and on the second insulation layer. The phase change layer is formed in and over the second holes in which the barrier layer is formed. The top electrodes are formed on the phase change layer.

Abstract: A phase-change memory device more precisely controls electrical current required to accomplish a phase change by using contact holes that extend between phase change layers that are sized differently from each other.

Abstract: A phase change memory device includes a semiconductor substrate having active regions and an isolation structure; gate lines extending in a direction perpendicular to the active regions; a source region and a drain region formed in a surface of each active region; a dot type lower electrode including a first contact plug formed in the drain region; second contact plugs formed in the source region and the isolation structure forming a line parallel to the gate line; a lower electrode contact formed on the lower electrode; a phase change layer and an upper electrode formed on the lower electrode contact; an upper electrode contact formed on the upper electrode; contacts for ground lines, formed between the active regions to come into contact with the second contact plugs; a bit line formed in the active region; and ground lines formed between the active regions.

Abstract: A phase change memory device having a word line contact includes an N+ base layer formed in a surface of a semiconductor substrate. A word line is formed over the N+ base layer. The word line contact is formed to connect the N+ base layer to the word line. The word line contact includes a first contact plug, a barrier layer formed on the first contact plug, and a second contact plug formed on the barrier layer coaxially with the first contact plug. The barrier layer prevents unwanted etching of the first contact plug when the second contact plug is being formed.