W deposition and titanium fluoride formation during WF6 reduction by Ti: Reaction path and mechanisms

Abstract

Reaction of WF 6 with air-exposed 27-and 250-nm-thick Ti films has been studied using Rutherford backscattering spectroscopy, scanning and high-resolution transmission electron microscopy, electron and x-ray diffraction, and x-ray photoelectron spectroscopy. We show that W nucleates and grows rapidly at localized sites on Ti during short WF 6 exposures ͑Ϸ6 s͒ at 445°C at low partial pressures p WF 6 Ͻ0.2 Torr. Large amounts of F, up to Ϸ2.0ϫ10 17 atoms/cm 2 corresponding to an average F/Ti ratio of 1.5 in a 27-nm-thick Ti layer, penetrate the Ti film, forming a solid solution and nonvolatile TiF 3. The large stresses developed due to volume expansion during fluorination of the Ti layer result in local delamination at the W/Ti and the Ti/SiO 2 interfaces at low and high WF 6 exposures, respectively. WF 6 exposure at p WF 6 Ͼ0.35 results in the formation of a network of elongated microcracks in the W film which allow WF 6 to diffuse through and attack the underlying Ti, consuming the 27-nm-thick Ti film through the evolution of gaseous TiF 4 .

Fluorination of MXene by Elemental F2 as Electrode Material for Lithium‐Ion Batteries

“…[34] This relativelyh igh BE peak can also be argued to be specifically related to TiF 3 ,w hich is electrochemically active. [35][36][37] The FMX6 and FMX24samples show Ti spectra containing peaks from only Ti 4 + ,w hich was shown to be from the compound TiOF 2 . [17,38] The Ti spectrac onfirm the absence of TiÀCb onds in FMX6 and FMX24 and show the formationo f TiOF 2 on these samples.…”

“…The spectrum of FMX3 contains an additional peak shifted towards higher BE at 460.8 eV that is related to fluorinated Ti . This relatively high BE peak can also be argued to be specifically related to TiF 3 , which is electrochemically active . The FMX6 and FMX24 samples show Ti spectra containing peaks from only Ti 4+ , which was shown to be from the compound TiOF 2 .…”

Directed Growth and Electrical‐ Transport Properties of Carbon Nanotube Architectures on Indium Tin Oxide Films on Silicon‐Based Substrates

“…Since sputtering is a physical-vapor-deposition process in which the atomic sticking coefficient is close to unity, penetration of a refractory metal such as Pt through the CNT film beyond 1±2 nm, either during deposition or by diffusion, is highly unlikely. [22] The room-temperature electrical characteristics are shown in Figure 3a. The differential conductance (G = dI/dV) plotted as a function of applied voltage, V 0 (see Fig. 3b), is essentially symmetrical about V 0 = 0, indicating the absence of Schottky barriers.…”

Investigation on critical thickness dependence of ALD TiN diffusion barrier in MOL

“…The transformation from Ti to TiF x compound creates ~ 230% volume expansion which leads to W delamination. Further exposure of underlying Ti to the precursor results in adverse volcanic defects [9,10]. In previous technology nodes, where thicker TiN (~few 100 nm) have been implemented, the presence of pinholes a.k.a.…”