Improvement of the Thermal Stability of NiSi by Germanium Ion Implantation

Abstract

The thermal stability of nickel monosilicide ͑NiSi͒ is one of the important research topics in the area of nano-complementary metal oxide semiconductor. This paper reports the effect of germanium ͑Ge͒ ion implantation on the thermal stability of the NiSi/Si structure. High dose Ge ion implantation ͑ Ͼ 5 ϫ 10 15 cm −2 ͒ can improve the thermal stability of the NiSi/Si structure. Ge ion implantation before NiSi formation results in a very smooth NiSi/Si interface due to Ge atom pileup at the NiSi/Si interface. This high concentration Ge layer reduces the interface energy so that the thermal stability can be improved. Both the phase-transformation temperature and agglomeration temperature are improved by 50-100°C. The effects of Ge ion implantation on the NiSi-contacted n + -p and p + -n shallow junctions are also examined. Although fast Ni diffusion via the ion implantation induced defects is observed, better thermal stability can still be observed on the n + -p junction.

Impact of a Germanium and Carbon Preamorphization Implant on the Electrical Characteristics of NiSi/Si Contacts With a Presilicide Sulfur Implant

“…The optimized implantation conditions of each species were selected based on prior reports [6], [7], [11], [12]. The Ge-implant condition was chosen to ensure that the amorphous layer is completely consumed within NiSi to avoid any residual EOR layer at the NiSi/Si interface.…”

“…Thus, NiSi should preferably withstand a higher thermal budget to enable a larger temperature process window for device integration. To increase the agglomeration temperature of NiSi films, preamorphization implant (PAI) of germanium (Ge) prior to Ni silicidation may be used [6]. Furthermore, the addition of carbon (C) after PAI also enhances the thermal stability of NiSi and removes the end-ofrange (EOR) defects in amorphized Si [7], [8].…”

Size Effect in Physical and Other Properties of Nanostructured Coatings

“…A large portion of Ni transfer is in the form of network penetration compared with penetration into the border of particles, and this can be due to the effects of swelling. The effects of swelling also depends on the structure, for instance for orthorhombic structure, the penetration ratio is low; therefore, the swelling ratio also decreases [24,34,35,[39][40][41][42][43][44][45][46][47].…”

Effect of Sn implantation on thermal stability improvement of NiSiGe

“…Substantial efforts were placed on the development of methods to improve the thermal stability and morphology of the silicide, e.g. by ion implantation [11][12][13][14]. However, little attention was devoted to the formation of NiSiGe by ion implantation.…”