Spin-dependent electron scattering in cobalt interconnects

Abstract

We use state-of-the-art ab initio simulation methods to study fundamental electron scattering mechanisms in cobalt conductors for applications in advanced interconnect technology. In particular, we consider electron scattering at intrinsic defect sites, twin grain boundaries, and at the Co/metal/Co interfaces present in vertical interconnects. Effective resistivity values and reflection coefficients are calculated in each case. The explicit treatment of electron spin results in distinct majority and minority spin behavior, with majority spin states exhibiting less scattering than minority states. Our results indicate that grain boundary scattering dominates over scattering at intrinsic point defect sites. Vertical resistance calculations indicate that Co vias can have substantially lower resistance than corresponding Cu vias at comparable dimensions. These results help build a fundamental understanding of electron scattering mechanisms in non-Cu conductors for advanced interconnect applications.

First-Principles Evaluation of fcc Ruthenium for its use in Advanced Interconnects

“…Figure 2(a) shows the calculated resistivity of fcc Ru against that of Cu, hcp Ru, Co, and W over a wide range of grain sizes. The values for bulk resistivity and mean free path of Cu, hcp Ru, Co, and W are taken from [8], and the shaded regions for each metal indicate the range of reflection coefficients calculated here for Ru and from previous studies for the Cu, Co, and W [22][23][24]. For large grain sizes where grain boundary scattering is negligible compared to inelastic phonon scattering, we see that the expected resistivity is strongly clustered around the values of bulk conductivity for each metal.…”

“…As interconnect widths shrink to the tens of nanometers and below, it is increasingly important to understand this less common phase. Studying the properties of fcc Ru can additionally provide valuable insight and direct comparison to other notable cubic BEOL conductors such as Cu, Co, and W [20][21][22][23][24].…”

“…(a) Resitivity of Cu, fcc Ru, hcp Ru, Co, and W as a function of average grain boundary using the Mayadas-Shatzkes model. For each metal, the shaded region covers the range of reflection coefficients computed in this work and previous studies[22][23][24]. (b) Expected line resistance due to grain boundary scattering.…”

Comparisons of enhanced thermal neutron‐ and gamma‐shielding properties in UHMWPE composites containing surface‐treated Sm2O3 and Gd2O3 particles

“…Nuclear technologies have been widely developed and utilized in a variety of applications, including the characterization of materials and agricultural products, 1,2 diagnosis and radiotherapy for cancers, 3,4 power generation, 5 national security, 6 and advanced scientific research 7,8 . Despite their great benefits, excessive exposure to ionizing radiations, especially neutrons and gamma rays, could severely affect users and electronic equipment, resulting in unpleasant side effects, such as malfunctions in equipment, abnormalities of internal organs, and casualties 9 .…”

Induction-Diffusion-Adsorption Process of Malachite Green for Cobalt Superconformal Electrodeposition

“…Among these metals with relatively low mean free path, Co was investigated widely as interconnect line after balancing the production cost and IC property. [6][7][8][9][10][11] Since cobalt not only is of low fine-line resistivity, but also is of strong electromigration resistance. 12,13 Applying electrodeposition method to prepare Co thin films is a cost-friendly, fast, and easy-operating method, and has been applied in many fields.…”