Schottky barrier heights of Pt and Ir silicides formed on Si/SiGe measured by internal photoemission

Abstract

Lowered-barrier-height silicide Schottky diodes are desirable for obtaining longer cutoff-wavelength Si-based infrared detectors. Silicide Schottky diodes have been fabricated by the reaction of evaporated Pt and Ir films on p-Si,-.Ge, alloys with a thin Si capping layer. The onset of metal-SiGe reactions was controlled by the deposited metal thickness. Internal photoemission measurements were made and the barrier heights were obtained from these. Pt-SiGe and Ir-SiGe reacted diodes have barrier heights of-0.27 and-0.31 eV, respectively, higher than typical values of 0.22 and 0.12 eV for the corresponding silicidelp-Si diodes. Their emission constants are also lower and more voltage dependent than silicide/Si diodes. PtSiiSQSiGe diodes, on the other hand, have lower barrier heights (-0.15 sV) than the PtSi/Si barrier height. The barrier height shifts in such silicide/Si/SiGe diodes are interpreted by accounting for tunneling through the unconsumed Si layer. This is done analytically using a simple model based on the Cohen, Vilms, and Archer (unpublished) modification to the Fowler equation, and leads to an extracted barrier height, that is! the Si barrier height reduced by the Si/SiGe band offset.

Influence of He-ion irradiation on the characteristics of Pd/n-Si0.90Ge0.10/Si Schottky contacts

“…It is, therefore, imperative to investigate the effect of ion implantation on the electrical characteristics of Metal/Si 1−x Ge x /Si SBDs. Although the electrical characterization of Schottky barrier junctions (SBJs) fabricated on non-implanted Si 1−x Ge x samples is well conducted [12][13][14], little is known about the effect of ion irradiation on the electrical properties of Schottky diodes fabricated on Si 1−x Ge x . Moreover, most of the studies of SBDs on Si 1−x Ge x were limited to the effect of Ge-content on the SBH.…”

Metal silicide patterning: a new approach to silicon nanoelectronics

“…The concept here is to manipulate the available density of states for carriers within the VFET channel by an applied gate voltage, rather than the barrier transmission probability as in the SB-MOSFET. Use of an ultra-thin silicon interfacial layer to alter the effective Schottky barrier height between a metal silicide and Si/Ge has been well established in recent work on infrared photodetectors [36]. Tunnel current density over the source in this device is relatively uniform as a function of position, with no pronounced 'hot spot' at the corner.…”

Schottky contact properties of Ni/n-poly-Si0.87Ge0.13/n-Si(100) heterostructure

“…Furthermore, formation and characterization of metal/ semiconductor interface have attracted considerable attention because of the scientific and technological significance [3]. In recent years, interfacial reaction and properties of Schottky contacts on Si 1 À x Ge x film for Pt, Pd, Ni, Ti, W, Al, Zr and Ir have been studied [4][5][6][7][8][9][10][11]. Most Si 1 À x Ge x films used in these research works are epitaxial and grown by molecular beam epitaxy (MBE) or chemical vapor deposition (CVD).…”