Formations and morphological stabilities of ultrathin CoSi ₂ films

Abstract

In this paper we investigate the formations and morphological stabilities of Co-silicide films using 1-8-nm thick Co layers sputter-deposited on silicon (100) substrates. These ultrathin Co-silicide films are formed via solid-state reaction of the deposited Co films with Si substrate at annealing temperatures from 450 °C to 850 °C. For a Co layer with a thickness no larger than 1 nm, epitaxially aligned CoSi2 films readily grow on silicon (100) substrate and exhibit good morphological stabilities up to 600 °C. For a Co layer thicker than 1 nm, polycrystalline CoSi and CoSi2 films are observed. The critical thickness below which epitaxially aligned CoSi2 film prevails is smaller than the reported critical thickness of the Ni layer for epitaxial alignment of NiSi2 on silicon (100) substrate. The larger lattice mismatch between the CoSi2 film and the silicon substrate is the root cause for the smaller critical thickness of the Co layer.

Characterisation of Electroless Deposited Cobalt by Hard and Soft X-ray Photoemission Spectroscopy

“…With the continued aggressive scaling toward smaller feature sizes, the need has arisen for alternative materials to copper to act as the interconnect metal. Various materials such as metal silicides [1,2], graphene [3] and Co [4,5] are currently being investigated to replace Cu. With such small dimensions it can be difficult for deposition techniques such as chemical and physical vapour deposition (CVD, PVD) to achieve seamless fill of high aspect ratio trenches.…”

Sputtering pressure influence on growth morphology, surface roughness, and electrical resistivity for strong anisotropy beryllium film

“…For the Be materials, the attention was focused mainly on the areas of the bulk materials founding, milling, bonding, and machining. [13][14][15][16][17][18] The sputtering pressure is one of the important parameters for the film fabrication, and has a remarkable influence on the microstructure of metal thin films, such as the grain orientation, crystal structure, grain size, and grain distribution. However, its effect is still unclear on the property of Be film with strong anisotropy.…”