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HL: Fachverband Halbleiterphysik

HL 8: Interfaces/ surfaces

HL 8.4: Talk

Monday, February 25, 2008, 14:45–15:00, EW 201

Schottky Barrier Height Engineering of NiSi/Si Contacts by Dopant Segregation — Christoph Urban, •Qing-Tai Zhao, Marcel Müller, Christian Sandow, and Siegfried Mantl — Institute of Bio- and Nanosystems (IBN1-IT), and CNI - Center of Nanoelectronic Systems for Information Technology, Forschungszentrum Jülich, D-52425 Jülich, Germany

Schottky barrier MOSFETs become more and more attractive for device downscaling, especially due to very low parasitic S/D resistances. However, the performance of such devices suffers from the on-current limitation due to tunneling through the high Schottky barrier at the source. The performance of such a device would be drastically improved if the effective Schottky barrier height (SBH) between the S/D metal and the semiconductor in the channel could be eliminated. A successful approach of SBH engineering is the silicidation induced dopant segregation (DS) where a thin highly doped layer is formed at the silicide-silicon interface. In this work we present a systematic study of effective SBH lowering by DS during Ni silicidation of activated and non-activated As and B implanted Si. The current-voltage characteristics of fabricated NiSi Schottky diodes show higher reverse saturation currents compared with Schottky diodes without DS. This confirms the distinct Schottky barrier lowering due to the silicide induced DS. Diodes where the dopants were not activated before silicidation show a minimum SBH of Φ=0.13eV for As and of Φ=0.14eV for B. Moreover, we observe that the diodes with dopants activated prior to silicidation show a remarkably lower SBH by about 35%.