Ultra-low (1.2×10−9 Ωcm2) p-Si0.55Ge0.45 contact resistivity (ρc) using nanosecond laser anneal for 7nm nodes and beyond

The recent FinFET scaling for 10-7nm node has resulted in significantly reduced contact areas for source/drain regions, leading to high contact resistance (Rc) [1-3]. Hence, it has become extremely critical to reduce the contact resistivity (ρ
_c
) to <; 1×10
^-9
Ω.cm
²
. ρ
_c
can be reduced by increasing the dopant concentration at the metal/semiconductor interface and by lowering the barrier height [4]. Several studies have reported improvements in NMOS ρ
_c
for Ti-based contacts using highly doped Si:P epi and advanced implant and activation techniques [5, 6]. For TiSi
₂
based contacts, the Schottky barrier height (SBH) for n-ype silicon is low; however, it is slightly higher for p type SiGe. Thus, there is a strong requirement to improve the PMOS ρ
_c
when Ti based contacts are used for both NMOS and PMOS.