Role of Carbon Pre-Germanidation Implantation on Enhancing the Thermal Stability of NiGe Films Below 10 nm Thickness

Abstract

The effects of carbon on improving the thermal stability of relatively thick NiGe films were manifested in previous work. How this thermal stability can be maintained for ultrathin NiGe films i.e. below 10 nm thickness, is, however, still unknown and deserves to be explored. In this work, the effects of carbon Pre-Germanidation Implantation (PGI) on the thermal stability of ultrathin NiGe films below 10 nm thickness were systematically studied. For different thicknesses of Ni layers, as-prepared NiGe films with carbon PGI were characterized by beans of sheet resistance measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM) and secondary ion mass spectroscopy (SIMS). The presence of carbon is proved to be still effective in enhancing the thermal stability of ultrathin NiGe films by ∼200 °C compared to the counterparts without C. The homogeneously distributed C at NiGe grain boundaries and C peak at the NiGe/Ge interface is responsible for such a distinguished improved thermal stability.

Ti Interlayer Mediated Uniform NiGe Formation under Low-Temperature Microwave Annealing

“…However, one major drawback of Ni x Ge y is its rough interface due to polycrystalline grains and agglomeration at high annealing temperatures (500-550 • C). It was reported that the thermal stability of Ni x Ge y on bulk Ge could be improved by pre-germanidation implantation [6], prior-germanidation fluorine implantation into Ge substrate [7], dopant segregation [8], or introducing other elements, such as titanium (Ti) [9], platinum (Pt) [10], tungsten (W) [11], tantalum (Ta) [11,12], cobalt (Co) [13], ytterbium (Yb) [14], and so on.…”