Nickel mono-silicide has been considered a promising silicide candidate for sub-90 nm nodes of integrated circuits manufacturing. To form high-quality nickel mono-silicide as source/drain contact electrodes, a two-step low temperature rapid thermal process has been proposed, in which the as-deposited Ni will react with silicon during a low temperature (<310 °C) first anneal. Due to the lower annealing temperature Ni2Si will form after the first anneal. To better control the silicidation process the growth kinetics of Ni2Si thin film fabricated by solid-state reaction of sputtered Ni thin film on n+/p junction at low temperature is investigated in this paper. It is demonstrated that between 260 and 280 °C the thickness of Ni2Si thin film has a linear rather than parabolic dependence on annealing time. The corresponding activation energy for this linear growth is found to be ∼1.35 eV.

The diffusion barrier properties for ultrathin Ru/Ta and Ru/TaN bilayer structure as the copper diffusion barrier are compared. Cu, Ru, Ta and TaN thin films are deposited by using the ion beam sputtering technique. The experimental results show that the thermal stability of the Cu/Ru/Ta or TaN /Si structure is much more improved than that of the Cu/Ru/Si structure without the interlayer. However, the Cu/Ru/TaN/Si shows better thermal stability than the Cu/Ru/Ta/Si structure, which should be attributed to the amorphous nature of the TaN interlayer. The microstructure evolution of the Cu/Ru/Ta (TaN)/Si structure during annealing is discussed. The results show that the Ru/TaN bilayer can be a very promising diffusion barrier in the future seedless Cu interconnect technology.

A multilayer structure of Co/a-Si/Ti/Si(100) together with Co/Ti/Si(100) is applied to investigate the process and mechanism of CoSi2 epitaxial growth on a Si(100) substrate. The experimental results show that by adding an amorphous Si layer with a certain thickness, the epitaxial quality of CoSi2 is significantly improved. A multi-element amorphous layer is formed by a solid state amorphization reaction at the initial stage of the multilayer reaction. This layer acts as a diffusion barrier, which controls the atomic interdiffusion of Co and Si and limits the supply of Co atoms. It has a vital effect on the multilayer reaction kinetics, and the epitaxial growth of CoSi2 on Si. The kinetics of the CoSi2 growth process from multilayer reactions is investigated.

Ultra-thin epitaxial CoSi2 films formed by Co(3∼5nm)/Ti(1 nm)/Si(100) and Co(3∼5nm)/Si(lnm)/Ti(Inm)/Si are studied. The multilayers are deposited by ion-beam sputtering. Rapid thermal annealing (RTA) is used for silicidation. XRD, RBS, TEM, AFM, four-point probe, I-V and C-V measurements are carried out for characterization. The XRD spectra show the CoSi2 film formed by Co/Ti/Si or Co/Si/Ti/Si solid phase epitaxy has, epitaxial characteristic. XTEM shows that the film is continuous. RBS/Channeling shows that the formed CoSi2 has sharp interface with a minimum channeling yield of Co signal of 40%. AFM shows that the surface of ultra-thin CoSi2 film is smooth with a roughness of nearly 0.7 nm. The Rs∼T relationship shows that the CoSi2 films formed by Co/Si/Ti/Si reaction have the best thermal stability (stable up to 900°C). Those formed by Co/Ti/Si reaction are stable up to 850°C, while those formed by Co/Si reaction are only stable up to 750°C. By fitting the experimental I-V and C-V curves of the epitaxial CoSi2/Si Schottky diodes, barrier heights of around 0.6 eV and close to unity ideality factors are obtained.

Ballistic electron emission microscopy (BEEM) and deep level transient spectroscopy (DLTS) have been used to study the effects of substrate damage introduced by an ion-milling process in PtSi/n-Si Schottky contacts. Argon ions with well-defined energies of 300, 500, 700, 1000, 1500 eV were used to sputter n-type Si substrates in an ion beam sputtering system before metal deposition and silicide formation. Histograms of the PtSi/n-Si Schottky barrier height (SBH) measured by BEEM show that the mean SBH decreases with increasing ion energy, which can be explained as a result of donor-like defects that are introduced by the ion milling treatment. From DLTS measurements, we found direct evidence for the presence of such defects.

The thermal stability of thin CoSi2 films formed from four layered structures: Co/Si, TiN/Co/Si, Co/Ti/Si and TiN/Co/Ti/Si has been studied using four-point-probe (FPP), TEM and RBS/channeling. It is found that thermal instability can be influenced by the polycrystalline structure in CoSi2. Growing epitaxial CoSi2 film on Si (100) using TiN capping and Ti interfacial layers can improve the thermal stability of thin CoSi2 film.

The ion-beam-sputtered polycrystalline SiGe film and its doping properties have been studied. Boron and phosphorus have been doped into the sputtered poly-SiGe film by ion implantation and diffusion. To activate the implanted impurities, both rapid thermal annealing and fiirnace annealing have been used. The electrical measurements show that boron and plhosphorus can be doped into sputtered SiGe films and effectively activated by both ion implantation with post-annealing and diffiision. Hall mobilities as high as 31 cm2/V-s and 20 cm2/V.s have been obtained in B-difflhsed and P-diffused SiGe films, respectively. The x-ray diffraction spectra of the sputtered Sifie filhn show its typical polycrystalline structure with (111), (220) and (311) as the preferential orientations.

A new method of epitaxial growth of CoSi2 film on Si substrate by ternary solid state interaction is investigated. XRD, RBS and TEM show that single-crystalline CoSi2 can be formed on both Si (111) and (100) substrates by using Co/Ti/Si or TiN/Co/Ti/Si multilayer. The evolution of multilayer structure and its resistivity is studied and epitaxy mechanism is discussed. Experimental results indicate strong affinity between Co and Si. During the ternary interaction the epitaxial CoSi2 can be grown directly on Si and its growth may behave as a diffusion controlled process. The thickness of Ti layer and the annealing procedure have important effect on CoSi2 epitaxial growth.

The CoSi2 thin film growth by Co/Si solid state interaction was investigated. The electrical and crystal properties of the films formed on (111) and (100) Si substrates were characterized after a rapid thermal annealing. A strong preferential CoSi2 (111) orientation grain growth was observed on (111)Si substrate. The formed CoSi2 film was highly conductive with a resistivity of 15.5 µΩ · cm.