Electronic and electrical properties of functional interfaces studied by hard X-ray photoemission

Abstract

a b s t r a c tAs the device downscaling in nanoelectronics has reached the 10 nm range, the functionality of materials employed in multilayered structures to be used in future logic and memory devices is largely defined by their interface properties. In particular, the electrical properties of the functional stacks are directly related to the electronic band line-up which is affected by the electric dipoles building up at the interface(s). In this work, hard X-ray photoelectron spectroscopy is applied to probe the electronic conditions at the interfaces of several relevant multilayered functional structures and to correlate the results with their electrical (transport) properties.

The new dedicated HAXPES beamline P22 at PETRAIII

“…2, left). A key feature of this instrument are HAXPES studies of device relevant multi-layer structures under working conditions by in-situ biasing and accurate electric characterization of electronic devices [16,17].…”

Recent applications of hard x-ray photoelectron spectroscopy

“…In these cases, the metal electrode deposited over the analysis area must be thick enough to ensure both continuity and low sheet resistance to avoid a potential drop across the sample. Such measurements have been performed to determine interface defect-state densities at SiO 2 /Si interfaces [34] and the chemical and electronic modifications responsible for the resistive switching in resistive random-access memory (ReRAM) [35][36][37][38]. In the latter application, films of Pt/Zr/HfO x /Si were studied by HAXPES with in situ biasing [38].…”

“…Such measurements have been performed to determine interface defect-state densities at SiO 2 /Si interfaces [34] and the chemical and electronic modifications responsible for the resistive switching in resistive random-access memory (ReRAM) [35][36][37][38]. In the latter application, films of Pt/Zr/HfO x /Si were studied by HAXPES with in situ biasing [38]. Ex situ electrical characterization showed switching between high and low resistive states; i.e., 'OFF' and 'ON,' respectively, with applied bias.…”

“…The authors therefore attributed the resistive switching to the formation of oxygen vacancies in the HfO x layer. [38].…”

Operando hard X-ray photoelectron spectroscopy study of the Pt/Ru/PbZr0.52Ti0.48O3 interface

“…Hard X-ray Photoelectron Spectroscopy (HAXPES) allows access to more deeply buried interfaces, 14 making the study of more realistic device architectures possible. Zenkevich et al 15 have measured the barrier-height at the top interface of a Pt/BTO/ Cr tunnel junction after ex situ switching. Interestingly, it was recently shown that applied bias gives rise to an additional core level shift due to the strain generated in a relaxor ferroelectric.…”