Novel Sn-Based Contact Structure for GeTe Phase Change Materials.

Germanium telluride (GeTe) is a phase change material (PCM) that has gained recent attention because of its incorporation as an active material for radio frequency (RF) switches, as well as memory and novel optoelectronic devices. Considering PCM-based RF switches, parasitic resistances from Ohmic contacts can be a limiting factor in device performance. Reduction of the contact resistance ( R) is therefore critical for reducing the on-state resistance to meet the requirements of high-frequency RF applications.

Impact of Premetallization Surface Preparation on Nickel-based Ohmic Contacts to Germanium Telluride: An X-ray Photoelectron Spectroscopic Study.

Surfaces of polycrystalline α-GeTe films were studied by X-ray photoelectron spectroscopy (XPS) after different treatments in an effort to understand the effect of premetallization surface treatments on the resistance of Ni-based contacts to GeTe. UV-O is often used to remove organic contaminants after lithography and prior to metallization; therefore, UV-O treatment was used first for 10 min prior to ex situ treatments, which led to oxidation of both Ge and Te to GeO (x < 2) and TeO, respectively. Then the oxides were removed by deionized (DI) HO, (NH)S, and HCl treatments.