C.R. Kim

Study of Nickel Silicide Thermal Stability Using Silicon-on-Insulator Substrate for Nanoscale Complementary Metal Oxide Semiconductor Field-Effect Transisor Device

The thermal stability of nickel silicide (NiSi) on a silicon-on-insulator (SOI) substrate after postsilicidation annealing (550–700 °C) is discussed in this paper. Nickel silicide technology, used for nanoscale complementary metal oxide semiconductor (CMOS) field-effect transistor (FET) devices, has a fundamental problem of thermal stability. Three different Pd concentrations in Ni–Pd alloy, 1, 5, and 10 at. %, were used to study the thermal stability of nickel silicide formed by a silicidation process. The Ni–Pd (10%) sample showed good thermal stability upon annealing at temperatures up to 700 °C for 30 min. Only a low-resistivity mononickel silicide (NiSi) phase peak was observed by X-ray diffraction (XRD) measurement, which was confirmed by Auger electron spectroscopy (AES) analysis. Uniformly formed nickel silicide with a good interface profile was obtained using the Ni–Pd (10%) sample according to field-emission scanning electron microscopy (FE-SEM) measurement. However, the Ni–Pd (5%) sample produced high-resistivity nickel disilicide (NiSi2) after annealing at 650 °C for 30 min. Four different layer structures, Ni, Ni/TiN, Ni/Co/TiN, and Ni–Pd (10%)/Co/TiN, were also used for further study. Among these structures, the Ni–Pd (10%)/Co/TiN layer structure had good thermal stability upon annealing at temperatures up to 700 °C, while the other structures deteriorated due to agglomeration above 550 °C.

Effects of Strained Silicon Layer on Nickel (Germano)silicide for Nanoscale Complementary Metal Oxide Semiconductor Field-Effect Transistor Device

The effects of a strained silicon layer on the thermal stability of nickel (germano)silicide for nanoscale complementary metal oxide semiconductor field-effect transistor (CMOSFET) devices are discussed in this study. Three different thicknesses, 5, 13, and 40 nm, of silicon layers on silicon germanium (SiGe) were prepared for this experiment. The effects of the silicidation rapid thermal annealing (RTA) temperature and postsilicidation annealing temperature for the different silicon layer thicknesses were studied. For comparison, a bulk silicon substrate and a SiGe substrate were also used. Silicides with the thin strained silicon layers (5 and 13 nm) on SiGe showed good thermal stability in this study. However, the other silicides using bulk silicon, 40-nm-thick silicon on SiGe, and the SiGe substrate underwent degradation due to silicide agglomeration during annealing. A SiO2 layer was found on the silicide using the SiGe substrate. In this study, several analysis methods such as four-point probe measurement, field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and Auger electron spectroscopy (AES) were used for detailed study.