Microstructure evolution of the Ir-inserted Ni suicides with additional annealing

Kijeong Yoon, Ohsung Song

Research output: Contribution to journalArticlepeer-review


Thermally-evaporated 10 nm-Ni/1 nm-Ir/(poly)Si structures were fabricated in order to investigate the thermal stability of Ir-inserted nickel suicide after additional annealing. The silicide samples underwent rapid thermal annealing at 300 °C to 1200 °C for 40 s, followed by 30 min annealing at the given RTA temperatures. Silicides suitable for the salicide process were formed on the top of the single crystal and polycrystalline silicon substrates, mimicking actives and gates. The sheet resistance was measured using a four-point probe. High resolution x-ray diffraction and Auger depth profiling were used for phase and chemical composition analysis, respectively. Transmission electron microscope and scanning probe microscope were used to determine the cross-section structure and surface roughness. The suicide, which formed on single crystal silicon substrate with surface agglomeration after additional annealing, could defer the transformation of Ni(Ir)Si to Ni(Ir)Si2 and was stable at temperatures up to 1200 °C. Moreover, the suicide thickness doubled. There were no outstanding changes in the silicide thickness on polycrystalline silicon. However, after additional annealing, the silicon-silicide mixing became serious and showed high resistance at temperatures >700 °C. Auger depth profiling confirmed the increased thickness of the silicide layers after additional annealing without a change in composition. For a single crystal silicon substrate, the sheet resistance increased slightly due to the significant increases in surface roughness caused by surface agglomeration after additional annealing. Otherwise, there were almost no changes in surface roughness on the polycrystalline silicon substrate. The Ir-inserted nickel monosilicide was able to maintain a low resistance in a wide temperature range and is considered suitable for the nano-thick silicide process.

Original languageEnglish
Pages (from-to)69-76
Number of pages8
JournalMetals and Materials International
Issue number1
StatePublished - Feb 2009


  • Additional annealing
  • Ir-inserted Ni suicide
  • Ni suicide
  • Salicide
  • Thermal stability


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