Extraction of correct Schottky barrier height of sulfur implanted NiSi/n-Si junctions: Junction doping rather than barrier height lowering

Abstract

Proper analysis of the Schottky barrier height extraction methods shows that sulfur implantation followed by anneal does not effectively reduce the Schottky barrier height of NiSi/n-Si contacts. Instead, the results for sulfur implanted samples are consistent with enhanced field emission due to an increased doping density of the surface region of the silicon. Sulfur has a large impact on contact resistivity for silicon with low initial doping concentration (<∼1017 cm−3), but little impact for silicon with high initial doping density (>∼1017 cm−3). Internal photoemission measurements show that the Schottky barrier height remains unchanged with sulfur implantation.

The physics and chemistry of the Schottky barrier height

“…144,307,[378][379][380][381][382][383][384][385][386][387][388][389][390] However, the net effect of interfacial chalcogen varied, as both significant increases 307 and decreases 386 in the n-type SBH were observed. To introduce impurities such as metals, [391][392][393][394][395] dopants, 348,389,390,[396][397][398][399][400][401][402][403][404] semiconducting, 405,406 and insulating 407 elements to the MS interface, various other methods have also been used, including deposition, ion implantation, segregation, etc. As shown in Fig.…”

Cold Silicon Preamorphization Implant and Presilicide Sulfur Implant for Advanced Nickel Silicide Contacts

“…5(b) shows the low temperature I -V characteristics. Detail of n B extraction method may be found in [15] and [27]- [35]. We used the currents in the reverse bias regime for the extraction of the effective n B [36], where the effects of series resistance and junction nonideality are not significant.…”

“…It has been reported that segregated sulfur (S) atoms at the NiSi/n + Si interface can reduce the effective SBH to ∼0.1 eV [6]- [14]. The S atoms near the interface could act as donor-like traps for narrowing the tunneling width of Schottky barrier [14] or enhance the effective doping concentration under the NiSi/Si interface [15]. Another important technique used in advanced contact formation is the preamorphization implant (PAI) before silicidation.…”

Impact of a Germanium and Carbon Preamorphization Implant on the Electrical Characteristics of NiSi/Si Contacts With a Presilicide Sulfur Implant

“…Manuscript On the other hand, it has been reported that introduction of sulfur (S) at the NiSi/n + Si interface can reduce the effective SBH or Φ n B to ∼0.1 eV [9]- [14]. S could act as a dopant to increase the thermionic field emission and tunneling current [15]. However, the impact of Ge and C PAI on the Φ n B reduction capability of S implant has not been investigated.…”