High-resistance phases of Ni-rich Ni silicide are formed on Si(100) below 400 °C, while high-resistance phases of Si-rich Ni silicide are formed above 600 °C. The desired low-resistance NiSi is formed between 400 °C and 600 °C. In this paper, the authors report the suppression of high-resistance phases of Ni silicide by passivating the Si(100) surface with a monolayer of Se. A 500-̊A Ni on n-type low 1015 cm-3 doped Si(100) wafers, passivated with Se, shows a sheet resistance of ∼ 2.55 Ω/square upon annealing between 200 °C and 500 °C, while the sheet resistance of the 500-̊A Ni on identical wafers without Se-passivation jumps to ∼ 7.92 Ω/square between 300 °C and 350 °C. Between 600 °C and 700 °C, the sheet resistance of the Se-passivated samples is ∼ 10% lower than that of the control samples. Transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy all confirm that the suppression of high-resistance Ni silicides below 500 °C is attributed to the suppression of silicidation and above 600 °C to the delay in Si-rich Ni silicide formation at the Ni/Se-passivated Si(100) interface.
- Integrated circuit metallization
- Nickel compounds
- Semiconductor-metal interfaces
- Surface treatment
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering