BEOL Compatible High-Performance Monolayer WSe2 pFETs with Record Gm=190 μS/μm and Ion=350 μA/μm by Direct-Growth on SiO2 Substrate at Reduced Temperatures

For the first time, we demonstrate excellent non-local CVD growth of p-type monolayer WSe
2
at reduced temperatures with BEOL compatibility, which is enabled by using stable mass flux of WO
2
Cl
2
precursor to increase the reaction rate during the monolayer WSe
2
growth at low temperature. High-quality monolayer WSe
2
can be grown at temperatures as low as 450 ℃ with film quality comparable to those by common growth methods at high temperatures with molten salt assistance. Based on this non-local growth method directly on SiO
2
, transfer-free high-performance monolayer WSe
2
p-FETs have been demonstrated with mobility of 57 cm
²
/Vs grown at 550 ℃ and 45 cm
²
/Vs grown at 450 ℃, 10 times higher than previous work at similar temperatures. The monolayer WSe
2
p-FET on 5 nm SiO
2
exhibits a record high transconductance of 190 μS/μm and on-state current of 350 μA/μm at V
ds
= -1 V, much higher than previous 2D TMDC transistors based on similar growth temperature. This work demonstrates high-performance monolayer WSe
2
pFETs based on BEOL compatible growth and fabrication without transfer, providing a new pathway for 2D TMDC CMOS circuit with integration capability.