Programmable metallization cell devices based on copper doped tungsten oxide

Programmable Metallization Cell (PMC) is a technology that is based on the electrochemical redistribution of nanoscale quantities of metals in devices containing solid electrolytes. A sandwich structure with a sliver or copper layer in contact with a solid electrolyte saturated with Ag+ or Cu+ ions and an inert electrode like tungsten make up a typical PMC device. These devices demonstrate a non volatile memory effect which is based on polarity-dependent resistance switching at small bias and current due to the electrodeposition of metals in the solid electrolyte. In this research, the same switching behavior which is governed by electrochemistry is demonstrated in new materials that alleviate some of the incompatibility issues with the silver doped chalcogenide glasses traditionally used in PMC devices. Investigations on copper doping in oxides of tungsten have resulted in PMC devices that are programmed to a low resistance in 100s of O at voltages lower than 1V and currents in the 10s of muA range. Low voltage and current operation, coupled with a high OFF/ON ratio and non-volatility of stored data make the PMC devices with Cu doped WO3 solid electrolytes ideal for the application of switching elements in reconfigurable systems and as non-volatile memories.