Metal/P-type GeSn Contacts with Ultra-low Specific Contact Resistivity

In this paper, we discuss the recent research progress in advanced metal/p-type GeSn contacts. The advantages of Sn incorporation on p
_c
reduction for metal/p-type GeSn contacts will be discussed. Ga and Sn surface segregation is achieved by optimizing the epitaxy of GeSn, leading to an ultra-low p
_c
value down to 6.5 x 10
^-10
Ω-cm
²
for metal/p-type GeSn contacts. In addition, Ga cold ion implantation at -100 °C is investigated for the development of a CMOS-compatible GeSn-based contact scheme with sub-10
^-9
Ω-cm
²
p
_c
for future advanced PFETs with GeSn S/D.