Ni(SiGeSn) Metal Contact Formation on Low Bandgap Strained (Si)Ge(Sn) Semiconductors

Abstract

GeSn has gained a lot of attention as alternative high mobility and low bandgap material to boost the performance of MOSFETs and Tunnel-FETs as well as photodetectors. Self-aligned contacts with low sheet resistance and good thermal stability are desired for GeSn FETs. We present the formation of metallic contacts for high mobility Sn-based group IV semiconductors. The formation of ternary NiGeSn alloys for Sn compositions from 6 to 9 at.% and quaternary NiSiGeSn alloys, formed on SiGeSn ternaries with large Si/Sn compositions ratios are presented.

(Si)GeSn nanostructures for light emitters

“…After contact window opening via optical lithography and CHF3 RIE, NiGeSn contacts were formed by sputtering of Ni and forming gas annealing at 325°C 15 . The last metallization step consists of 200 nm Al.…”

Ni/GeSn solid-state reaction monitored by combined X-ray diffraction analyses: focus on the Ni-rich phase

“…For the Ni/Ge 1Àx Sn x system, most previous studies state that the Ni-rich phase corresponds to the Ni 5 (GeSn) 3 phase (Demeulemeester et al, 2011;Wirths et al, 2014;Wirths, Troitsch et al, 2015;Liu et al, 2014). When indexed, the latter is related to the monoclinic structure, which is stable at room temperature (Liu et al, 2014;Wirths, Troitsch et al, 2015).…”

“…temperatures below 523 K). Nishimura et al (2011) found an epitaxial Ni 2 (GeSn) formation in samples with an Sn content of 3.6%, while different studies reported that the Ni-rich phase corresponds to Ni 5 (GeSn) 3 (Demeulemeester et al, 2011;Wirths et al, 2014;Wirths, Troitsch et al, 2015;Liu et al, 2014). In addition, Schulte-Braucks et al (2017) confirmed the presence of Ni 5 (GeSn) 3 with the appearance of supplementary peaks that could be attributed to Ni 2 (GeSn) or Ni 3 (GeSn) 2 .…”

Texture of NiGe(Sn) on Ge(100) and its evolution with Sn content

“…The possibility of obtaining low resistive values when using nickel makes the contacts a key module to achieve high performance (Vincent et al, 2011;Demeulemeester et al, 2011;Han et al, 2011). Ni/Ge or Ni/GeSn contacts are formed by a solid-state reaction during which Ni 1Àx Ge x or Ni 1Àx (GeSn) x polycrystalline layers are obtained (Balakrisnan et al, 2005;Gaudet et al, 2006;De Schutter, Van Stiphout et al, 2016;van Stiphout et al, 2017;Nishimura et al, 2011;Wirths et al, 2014;Wirths, Geiger et al, 2015;Liu et al, 2015;Quintero et al, 2018c). In order to understand the properties of these polycrystalline films, it is essential to have a good understanding of their microstructure.…”

“…Meanwhile, in-depth studies concerning the texture of the monostanogermanide phase are not available. Wirths and coworkers showed that the Ni(SiGeSn) layer was not in an epitaxial relationship with the SiGeSn layer underneath (Wirths et al, 2014;Wirths, Troitsch et al, 2015). Liu et al (2015) reported variations of intensity for some diffraction peaks between reference and carbon-implanted samples.…”