First-principles predictions of ruthenium-phosphorus and ruthenium-boron glassy structures and chemical vapor deposition of thin amorphous ruthenium-boron alloy films

Abstract

First-principles density-functional calculations are presented revealing that Ru(P) and Ru(B) alloys with moderate P or B content can result in a glassy structure exhibiting strong chemical short-to-medium range order. Amorphous phases are predicted to be energetically more favorable than the crystalline counterparts for the Ru(P) and Ru(B) alloys above ~20 at.% P and ~10 at.% B. The relative stability of amorphous and crystalline Ru(B) alloys is examined along with local atomic ordering in the amorphous alloys. The growth of ultrathin (3nm) amorphous Ru(B) alloy films of varying B concentration via chemical vapor deposition is explored using Ru 3 (CO) 12 and B 2 H 6 as the Ru and B sources, respectively. Experiments reveal the films grown at 250 C are amorphous at B contents in excess of 15 at.% and polycrystalline below 10 at.% B, consistent with first-principles predictions. Amorphous Ru(B) films remain amorphous following annealing at 450 °C and become polycrystalline at 500 °C. Film resistivity ranged from 40 to 120 μΩ-cm and was independent of B loading. Electric field stress tests to failure for Cu/3-nm Ru(B)/SiO 2 /Si stacks are used to indicate suitability of Ru(B) as a copper diffusion barrier layer.

Effect of deposition parameters on surface roughness and consequent electromagnetic performance of capacitive RF MEMS switches: a review

“…Deposition is the most commonly applied process during the fabrication of thin films. According to the thin-film forming mechanism, deposition can be classified into chemical vapor deposition (CVD), such as low pressure CVD [38] and plasma enhanced CVD (PECVD) [39], and physical vapor deposition such as sputtering deposition [40][41][42], ion beam sputtering [43,44], thermal evaporation [45,46], pulsed laser deposition (PLD) [47,48], etc. This review mainly focuses on sputtering deposition and some other deposition processes are also proposed.…”

Recent Advances in Barrier Layer of Cu Interconnects

“…Many studies [118][119][120][121][122][123][124] have demonstrated that some foreign elements, such as boron (B), phosphorus (P) and carbon (C) are able to induce the formation of amorphous Ru thin films and thereby significantly improve the ability of Ru thin films to prevent Cu interdiffusion. A 12 nm thin film of Ru (P) deposited on a low-κ dielectric layer effectively prevented the diffusion of Cu into Si wafer at 800 • C for 5 min [124].…”

Ruthenium(II) MOCVD Precursors for Phosphorus‐Doped Ruthenium Layer Formation

“…[15][16][17] Density-functional theory (DFT) calculations reveal that an amorphous layer structure is favorable, when the film shows a content of 20 at-% phosphorus. [18][19][20] Recently, a few studies for the formation of phosphorusdoped ruthenium layers by applying the PVD (= physical vapor deposition), CVD (= chemical vapor deposition) or ALD (= atomic layer deposition) process were reported. [16,17,21] In general, a dual source approach for Ru(P) thin film formation was implemented by using the triangular cluster Ru 3 (CO) 12 and different phosphines as precursors.…”

“…One possibility for layer improvement is to dope ruthenium films with phosphorus, since such deposits provide a better inhibition of copper diffusion . Density‐functional theory (DFT) calculations reveal that an amorphous layer structure is favorable, when the film shows a content of 20 at‐% phosphorus …”