Abstract: A phase change memory may be formed of a phase change material alloy that produces a higher threshold voltage and, in some cases, is operable at higher temperatures. For example, the formulation may include a poor metal, antimony, and at least one of tellurium or selenium.

Abstract: A phase change memory formed by a plurality of phase change memory devices having a chalcogenide memory region extending over an own heater. The heaters have all a relatively uniform height. The height uniformity is achieved by forming the heaters within pores in an insulator that includes an etch stop layer and a sacrificial layer. The sacrificial layer is removed through an etching process such as chemical mechanical planarization. Since the etch stop layer may be formed in a repeatable way and is common across all the devices on a wafer, considerable uniformity is achieved in heater height. Heater height uniformity results in more uniformity in programmed memory characteristics.

Abstract: Crossing trenches of different depths may be formed in the same semiconductor structure by etching the deeper trench first. The deeper trench and the substrate may then be covered with a material that prevents further etching. The covering is etched through for the shallower trench, leaving a protective covering in the deeper trench.

Abstract: Both a chalcogenide select device (24, 120) and a chalcogenide memory element (40, 130) are formed within vias within dielectrics (18, 22). As a result, the chalcogenides is effectively trapped within the vias and no glue or adhesion layer is needed. Moreover, delamination problems are avoided. A lance material (30) is formed within the same via (31) with the memory element (40, 130). In one embodiment, the lance material is made thinner by virtue of the presence of a sidewall spacer (28); in another embodiment no sidewall spacer is utilized. A relatively small area of contact between the chalcogenide (40) used to form a memory element (130) and the lance material (30) is achieved by providing a pin hole opening in a dielectric (34), which separates the chalcogenide and the lance material.

Abstract: A phase change memory may be formed to have a dimension that is sub-lithographic in one embodiment by forming a surface feature over the phase change material, and coating the surface feature with a mask of sub-lithographic dimensions. The horizontal portions of the mask and the surface feature may then be removed and the remaining portions of the mask may be used to define a dimension of said phase change material. Another dimension of the phase change material may be defined using an upper electrode extending over said phase change material as a mask to etch the phase change material.

Abstract: A memory may be implemented with a stable chalcogenide glass which is defined as a generally amorphous chalcogenide material that does not change to a generally crystalline phase when exposed to 200° C. for 30 minutes or less. Different states may be programmed by changing the threshold voltage of the material. The threshold voltage may be changed with pulses of different amplitude and/or different pulse fall times. Reading may be done using a reference level between the threshold voltages of the two different states. A separate access device is generally not needed.

Abstract: A phase change memory may be made using an isolation diode in the form of a Schottky diode between a memory cell and a word line. The use of Schottky diode isolation devices may make the memory more scaleable in some embodiments.

Abstract: A phase change memory may be formed to have a dimension that is sub-lithographic in one embodiment by forming a surface feature over the phase change material, and coating the surface feature with a mask of sub-lithographic dimensions. The horizontal portions of the mask and the surface feature may then be removed and the remaining portions of the mask may be used to define a dimension of said phase change material. Another dimension of the phase change material may be defined using an upper electrode extending over said phase change material as a mask to etch the phase change material.

Abstract: A phase change material may include a pore formed of a relatively smaller phase change material and a relatively larger resistance heater. As a result, the relatively smaller portion of phase change material may have improved properties.

Abstract: A phase change material may include a pore formed of a relatively smaller phase change material and a relatively larger resistance heater. As a result, the relatively smaller portion of phase change material may have improved properties.

Abstract: An ovonic threshold switch may be formed of a continuous chalcogenide layer. That layer spans multiple cells, forming a phase change memory. In other words, the ovonic threshold switch may be formed of a chalcogenide layer which extends, uninterrupted, over numerous cells of a phase change memory.

Abstract: A phase change memory with higher column landing margin may be formed. In one approach, the column landing margin may be increased by increasing the height of an electrode. For example, the electrode being made of two disparate materials, one of which includes nitride and the other of which does not. In another approach, a hard mask is used which is of substantially the same material as an overlying and surrounding insulator. The hard mask and an underlying phase change material are protected by a sidewall spacer of a different material than the hard mask. If the hard mask and the insulator have substantially the same etch characteristics, the hard mask may be removed while maintaining the protective character of the sidewall spacer.

Abstract: A phase change material may be formed within a trench in a first layer to form a damascene memory element and in an overlying layer to form a threshold device. Below the first layer may be a wall heater. The wall heater that heats the overlying phase change material may be formed in a U-shape in some embodiments of the present invention. The phase change material for the memory element may be elongated in one direction to provide greater alignment tolerances with said heater and said threshold device.

Abstract: A small critical dimension element, such as a heater for an ovonic unified memory, may be formed within a pore by using successive sidewall spacers. The use of at least two successive spacers enables the limitations imposed by lithography and the limitations imposed by bread loafing to be overcome to provide reduced critical dimension elements.

Abstract: A phase change memory may be made of a chalcogenide material having a U-shape. The U-shaped chalcogenide may transition between amorphous and crystalline phases in an upper part of a vertical portion thereof. As a result, in some embodiments, self-heating may be achieved without the need for a heater, and without the need for glue in some cases.

Abstract: A phase change memory may be formed which is amenable to multilevel programming. The phase change material may be formed with a lateral extent which does not exceed the lateral extent of an underlying heater. As a result, the possibility of current bypassing the amorphous phase change material in the reset state is reduced, reducing the programming current that is necessary to prevent this situation. In addition, a more controllable multilevel phase change memory may be formed in some embodiments.

Abstract: A dual resistance heater for a phase change material region is formed by depositing a resistive material. The heater material is then exposed to an implantation or plasma which increases the resistance of the surface of the heater material relative to the remainder of the heater material. As a result, the portion of the heater material approximate to the phase change material region is a highly effective heater because of its high resistance, but the bulk of the heater material is not as resistive and, thus, does not increase the voltage drop and the current usage of the device.

Abstract: A phase change material may be formed within a trench in a first layer to form a damascene memory element and in an overlying layer to form a threshold device. Below the first layer may be a wall heater. The wall heater that heats the overlying phase change material may be formed in a U-shape in some embodiments of the present invention. The phase change material for the memory element may be elongated in one direction to provide greater alignment tolerances with said heater and said threshold device.

Abstract: A phase change memory may be formed to have a dimension that is sub-lithographic in one embodiment by forming a surface feature over the phase change material, and coating the surface feature with a mask of sub-lithographic dimensions. The horizontal portions of the mask and the surface feature may then be removed and the remaining portions of the mask may be used to define a dimension of said phase change material. Another dimension of the phase change material may be defined using an upper electrode extending over said phase change material as a mask to etch the phase change material.

Abstract: A phase change memory may be made using an isolation diode in the form of a Shottky diode between a memory cell and a word line. To reduce the leakage currents associated with the Shottky diode, a guard ring may be utilized.