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 multilevel phase change memory cell may have a plurality of intermediate levels between a set and a reset or a crystalline and amorphous states. These intermediate levels between set and reset may be differentiated not only by programming current, but also by different programming pulse widths. As a result, the intermediate states may be positioned, on the programming current versus programming pulse width curve, in regions of common resistance with a relatively large range of programming current.

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 ring shaped heater surrounds a chalcogenide region along the length of a cylindrical solid phase portion thereof defining a change phase memory element. The chalcogenide region is formed in a sub-lithographic pore, so that a relatively compact structure is achieved. Furthermore, the ring contact between the heater and the cylindrical solid phase portion results in a more gradual transition of resistance versus programming current, enabling multilevel memories to be formed.

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 device may be formed by forming a phase change material and an electrode in a pore in an insulator. The phase change material fills less of the pore than the electrode.

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: Both a chalcogenide select device and a chalcogenide memory element are formed within vias within dielectrics. 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 is formed within the same via with the memory element. In one embodiment, the lance material is made thinner by virtue of the presence of a sidewall spacer; in another embodiment no sidewall spacer is utilized. A relatively small area of contact between the chalcogenide used to form a memory element and the lance material is achieved by providing a pin hole opening in a dielectric, which separates the chalcogenide and the lance material.

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 seasoned phase change memory has been subjected to a longer pulse to adjust resistance levels prior to use of the phase change memory.

Abstract: Disturb from the reset to the set state may be reduced by creating an amorphous phase that is substantially free of crystal nuclei when programming the reset state in a phase change memory. In some embodiments, this can be achieved by using a current or a voltage to program that exceeds the threshold voltage of the phase change memory element, but does not exceed a safe current voltage which would cause a disturb.

Abstract: A phase change memory in the reset state may be heated to reduce or eliminate electrical drift.

Abstract: A multilevel phase change memory cell may have a plurality of intermediate levels between a set and a reset or a crystalline and amorphous states. These intermediate levels between set and reset may be differentiated not only by programming current, but also by different programming pulse widths. As a result, the intermediate states may be positioned, on the programming current versus programming pulse width curve, in regions of common resistance with a relatively large range of programming current.

Abstract: A phase change memory may be formed with an insulator made up of two different layers having significantly different thermal conductivities. Pores may be formed within the stack of insulating layers and the pores may be filled with heaters, chalcogenide layers, and electrodes in some embodiments. The use of the two different insulator layers enables embodiments where thermal losses may be reduced and an amorphous region may be maintained along the entire length of the phase change material layer.

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 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 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 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 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 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.