Nano-Scale Surface Morphology Evolution of Cu/Ti Thin Films

Abstract

This paper discusses solid-phase reaction, agglomeration and dendritic growth of Cu/Ti/Si thin films with different sublayer thickness, 70 nm Cu/20 nm Ti/Si and 20 nm Cu/70 nm Ti/Si, annealed using rapid thermal annealing (RTA) method at the temperature from 500 degrees C to 800 degrees C. The crystal structure is examined using XRD, and the surface morphology is measured by SEM and AFM. The sheet resistance is measured using four-point probe method. The dendritic patterns can be obtained in both thin films at high temperature but the density is not similar. For 70 nm Cu/20 nm Ti/Si thin films, Cu agglomerates at the annealed temperature upon to 700 degrees C and thin film is still crystalline after 800 degrees C. For 20 nm Cu/70 nm Ti/Si thin films, Cu agglomerated completely only after 500 degrees C and thin film has amorphous structure annealed after 800 degrees C.

Phase Field Simulation on the Surface Morphology of Cu/Ti Nano Thin Film

“…It is shown that the surface roughness is influenced by thickness of Ti layer and Cu layer in the double-layer heterostructure. The simulated surface morphology and roughness shows a good agreement with micrographs and measured data of experiments [1].…”

“…The surface morphology of nano-thin films has great influence on the physical/chemical properties of the thin film system [1][2][3]. However, the mechanism controlling the surface morphology/roughness of the heterostructure films is still not clear.…”

“…Cu/Ti binary thin film system is widely used in micro-/nano-electro mechanical systems (MEMS/NEMS), microelectronics and optoelectronics [1,13]. It should be note that pure Cu exhibits poor adhesion to silicon dioxide (SiO2) but Ti is easy to react with SiO2 to produce thin barrier metal layers in SiO2-based low-k interlayers.…”

Agglomeration and Dendritic Growth of Cu/Ti/Si Thin Film

“…According to Fan et al [29], Sun et al [32], and Umar and Oyama [33], Journal of Nanomaterials Heat absorption of a system can be given as = Δ , where is specific heat capacity, is the mass related to the thickness, and Δ is the change of temperature. In the 70 nmCu/20 nmTi/Si film system reported in our previous research [27], the thickness of Si substrate (0.4 mm) is bigger than the film thickness for several orders of magnitude, so the substrate will play a major role in the endothermic process. For the same absorption heat, when the substrate thickness increases, the change of temperature becomes smaller.…”

“…In our previous research [27], two Cu/Ti thin film systems (70 nmCu/20 nmTi/0.4 mmSi ⟨100⟩ and 20 nmCu/ 70 nmTi/0.6 mmSi ⟨100⟩) were deposited. The surface morphology evolution of the two thin films was different.…”