An apparatus including a contact on a substrate, a dielectric material overlying the contact, a phase change element overlying the dielectric material on a substrate, and a heater element disposed in the dielectric material and coupled to the contact and the phase change element, wherein a portion of the dielectric material comprises a thermal conductivity less than silicon dioxide. A method including introducing over a contact formed on a substrate, a dielectric material, a portion of which comprises a thermal conductivity less than silicon dioxide, introducing a heater element through the dielectric material to the contact, and introducing a phase change material over the dielectric material and the heater element.
Phase change memories may exhibit improved properties and lower cost in some cases by forming the phase change material layers in a planar configuration. A heater may be provided below the phase change material layers to appropriately heat the material to induce the phase changes. The heater may be coupled to an appropriate conductor.
The memory device has constituent cells which include a structural phase-change material to store the cells data. This material may be, for instance, a chalcogenide alloy. A first pulse is applied to the cell to leave the material in a first state, such as a reset state in which the material is relatively amorphous and has relatively high resistivity. Thereafter, a second pulse is applied to the cell to change the material from the first state to a second, different state, such as a set state in which the material is relatively crystalline and has relatively low resistivity. This second pulse has a generally triangular shape, rather than a rectangular one.
A memory array is operated by increasing a number of currents through a number of corresponding cells of the array, where each cell has a structural phase-change material to store data for that cell. Each of the currents are increased to an upper level that is sufficiently high that can cause the corresponding cell to be in a first state. Some of the currents are decreased to lower levels at sufficiently high rates that cause their corresponding cells to be programmed to the first state, while others are decreased at sufficiently low rates that cause their corresponding cells to be programmed to a second state.
A semiconductor memory device capable of achieving high integration is provided. A semiconductor memory device is provided with: a silicon substrate; bipolar transistors formed on the silicon substrate; an interlayer insulating film which has contact holes accepting parts of the bipolar transistors and reaching a surface of the silicon substrate, and which is formed on the silicon substrate; and storage elements electrically connected to the bipolar transistors. The storage elements have a first state in which an electrical resistance is relatively high and a second state in which an electrical resistance is relatively low.
An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.
