X‐ray photoelectron spectroscopy analysis of Ge–Sb–Se pulsed laser deposited thin films

Abstract

Pulsed laser deposition was used to prepare amorphous thin films from (GeSe 2 ) 100Àx (Sb 2 Se 3 ) x system (x = 0, 5, 10, 20, 30, 40, 50, and 60). From a wide variety of chalcogenide glass-forming systems, Ge-Sb-Se one, especially in thin films form, already proved to offer a great potential for photonic devices such as chemical sensors. This system has a large glass-forming region which gives the possibility to adjust the chemical composition of the glasses according to required physical characteristics. The chemical composition of fabricated thin films was analyzed via X-ray photoelectron spectroscopy (XPS) and compared to energy dispersive spectroscopy (EDS) data. The results of both techniques agree well: a small deficiency in chalcogen element and an excess of antimony was found. The structure of as-deposited thin films has been investigated by XPS. The presence of the two main structural units, [GeSe 4 ] and [SbSe 3 ] proposed by Raman scattering spectroscopy data analysis, was confirmed by XPS. Moreover, XPS core level spectra analysis revealed the presence of M-M bonds (M = Ge, Sb) in (Ge,Sb)-Ge-(Se) 3 and (Ge,Sb)-Sb-(Se) 2 entities that could correspond to Ge-based tetrahedra and Sb-based pyramids where one of its Se atoms at corners is substituted by Ge or Sb ones. The content of depicted M-M bonds tends to increase with introduction of antimony in the amorphous network of as-deposited thin films from x = 0 to x = 40 and then it decreases. XPS analysis of as-deposited thin films shows also the presence of the (Ge,Sb)-Se-(Ge,Sb) and Se-Se-(Ge,Sb) entities.

Etching of GeSe2 chalcogenide glass and its pulsed laser deposited thin films in SF6, SF6/Ar and SF6/O2 plasmas

“…Ge-Se thin films, with a thickness of 1 µm, were deposited by PLD, via ablating a GeSe 2 bulk target with an excimer laser (COMPex 205, Coherent) operating at 248 nm. The details of glass target fabrication and PLD process are given elsewhere [14]. In a previous study, the composition of Ge 39 Se 61 thin films was determined using a scanning electron microscope with an energy-dispersive X-ray analyzer (EDS, JSM 6400-OXFORD Link INCA).…”

“…Aiming for low-cost and miniaturized devices, deposition and patterning techniques make possible fabrications of integrated multiple components onto the same substrate, contributing to the development of complex integrated optical platforms. Most of deposition processes are based on physical vapor deposition method as thermal evaporation [9,10], sputtering [11,12], Pulsed Laser Deposition (PLD) [13,14]. As patterning method, plasma etching can provide an anisotropic sidewall profile on dielectric materials with low sidewall roughness.…”

Surface composition and micromasking effect during the etching of amorphous Ge-Sb-Se thin films in SF6 and SF6/Ar plasmas

“…Ge 19 Sb 21 Se 60 thin films with a thickness of~1.5 µm were deposited by pulsed laser deposition, by ablating a Ge 19.5 Sb 17.8 Se 62.7 bulk target with a KrF excimer laser (Compex 102, Lambda Physik) [18]. The composition of the thin films (± 1%) and the bulk target (± 0.5%) were determined by Energy Dispersive X-ray Spectroscopy (JSM 6400-OXFORD Link INCA).…”

“…2 after etching. Literature concerning the XPS analysis of Ge-Sb-Se system shows that SbSe 3/2 pyramids and GeSe 4/2 tetrahedra are the dominant motifs [18,31,32]. The quantification of relative atomic percentages shows a Ge-depletion considering Ge, Sb and Se elements.…”

“…The nonetched Ge-Sb-Se thin film is decomposed with two distinct environments Se-Se-(Ge, Sb) (BE = 53.8 eV) and Se-(Ge, Sb) 2 (BE = 54.6 eV). It has been shown that the BE values of the two entities depend on the composition of the investigated Ge-Sb-Se material [18,31,32,38].…”