A display apparatus includes a reflective layer with reflective material. One or more stacks of additional layers are provided on the reflective layer. Each stack has an optically switchable layer. A plurality of switching elements are located on a side of the reflective layer opposite to the one or more stacks or form part of the reflective layer. Each switching element is operable to apply heating to a switchable portion of the optically switchable layer and thereby change an appearance of the switchable portion when viewed from a viewing side of the display apparatus. The apparatus applies the heating by driving an electrical current through the switching element to generate Joule heating in the switching element. The electrical current flows in an electrical circuit including a portion of the reflective layer.

A resistive random-access memory (ReRAM) device may include a thermally engineered layer that is positioned adjacent to an active layer and configured to act as a heat sink during filament formation in response to applied voltages. The thermally engineered layer may act as one of the electrodes on the ReRAM device and may be adjacent to any side of the active layer. The active layer may also include a plurality of individual active layers. Each of the active layers may be associated with a different dielectric constant, such that the middle active layer has a dielectric constant that is significantly higher than the other two surrounding active layers.

A circuit according to the present application includes a diode or other non-linear device coupled to a heating element of a phase-change material (PCM) radio frequency (RF) switch. The diode or other non-linear device allows an amorphizing pulse or a crystallizing pulse to pass to a first terminal of the heating element. The diode or other non-linear device substantially prevents a pulse generator providing the amorphizing pulse or crystallizing pulse from interfering with RF signals at RF terminals of the PCM RF switch. In an array of PCM cells each including a diode or other non-linear device, the diode or other non-linear device substantially prevents sneak paths that would otherwise enable an amorphizing or crystallizing pulse intended for a heating element of a selected cell of the array to be provided to heating elements of unselected cells of the array.

A method for fabricating a semiconductor device includes forming first contacts to a heater for programming, and forming second contacts to a phase-change material layer for resistance readout. The phase-change material layer is formed in proximity to the heater, and the first contacts are electrically isolated from the second contacts to provide separate programming and resistance readout control.

A radio frequency (RF) device includes a phase-change material (PCM) situated over a sheet of thermally conductive and electrically insulating material, a heating element situated under the sheet of thermally conductive and electrically insulating material, and an input/output terminal situated over the PCM. The heating element is situated in a dielectric. A heat spreader is situated under the dielectric and over a substrate. Metal interconnect layers can be situated under and/or over the PCM, with the substrate situated below the metal interconnect layers.

A phase-change material (PCM) switching device is provided. The PCM switching device includes: a base dielectric layer over a semiconductor substrate; a heater element embedded in the base dielectric layer, the heater element comprising a first metal element and configured to generate heat in response to a current flowing therethrough; a self-aligned dielectric layer disposed on the heater element, wherein the self-aligned dielectric layer comprises one of an oxide of the first metal element and a nitride of the first metal element, and the self-aligned dielectric layer is horizontally aligned with the heater element; a PCM region disposed on the self-aligned dielectric layer, wherein the PCM region comprises a PCM operable to switch between an amorphous state and a crystalline state in response to the heat generated by the heater element; and two metal pads electrically connected to the PCM region.

There are disclosed herein various implementations of a semiconductor device including a group III-V layer situated over a substrate, and a phase-change material (PCM) radio frequency (RF) switch situated over the group III-V layer. The PCM RF switch couples a group III-V transistor situated over the group III-V layer to one of an integrated passive element or another group III-V transistor situated over the group III-V layer. The PCM RF switch includes a heating element transverse to the PCM, the heating element underlying an active segment of the PCM. The PCM RF switch is configured to be electrically conductive when the active segment of the PCM is in a crystalline state, and to be electrically insulative when the active segment of the PCM is in an amorphous state.

A radio frequency (RF) switching circuit includes stacked phase-change material (PCM) RF switches. The stacked PCM RF switches can include a high shunt capacitance PCM RF switch having its heating element contacts near its PCM contacts, and a low shunt capacitance PCM RF switch having its heating element contacts far from its PCM contacts. An RF voltage is substantially uniformly distributed between the high shunt capacitance PCM RF switch and the low shunt capacitance PCM RF switch. The stacked PCM RF switches can also include a wide heating element PCM RF switch having a large PCM active segment, and a narrow heating element PCM RF switch having a small PCM active segment. The wide heating element PCM RF switch will have a higher breakdown voltage than the narrow heating element PCM RF switch.

A radio frequency (RF) switch includes a heating element, an aluminum nitride layer situated over the heating element, and a phase-change material (PCM) situated over the aluminum nitride layer. An inside segment of the heating element underlies an active segment of the PCM, and an intermediate segment of the heating element is situated between a terminal segment of the heating element and the inside segment of the heating element. The aluminum nitride layer situated over the inside segment of the heating element provides thermal conductivity and electrical insulation between the heating element and the active segment of the PCM. The aluminum nitride layer extends into the intermediate segment of the heating element and provides chemical protection to the intermediate segment of the heating element, such that the intermediate segment of the heating element remains substantially unetched and with substantially same thickness as the inside segment.

Some embodiments relate to a memory device. The memory device includes a programmable metallization cell random access memory (PMCRAM) cell. The programmable metallization cell comprises a dielectric layer disposed over a bottom electrode, the dielectric layer contains a central region. A conductive bridge is formable and erasable within the dielectric layer and the conductive bridge is contained within the central region of the dielectric layer. A metal layer is disposed over the dielectric layer. A heat dispersion layer is disposed between the bottom electrode and the dielectric layer.