High-Performance $\hbox{GeO}_{2}/\hbox{Ge}$ nMOSFETs With Source/Drain Junctions Formed by Gas-Phase Doping

We reveal that the MOVPE-based gas-phase doping can yield lower arsenic diffusion constant and lower leakage current n
⁺
/p junctions in Ge compared with conventional ion-implantation doping. Thus, the gas-phase doping is quite effective for realizing high-performance Ge n-channel MOSFETs. By using gas-phase doping for source/drain junction formation, the (100) GeO
₂
/Ge nMOSFETs have achieved high electron mobility of 1020 cm
²
/V·s while maintaining low junction leakage current and high I
_on
/I
_off
ratio of 10
⁵
. Furthermore, the (110) GeO
₂
/Ge nMOSFETs have also shown high electron mobility and high I
_on
/I
_off
ratio.