Integration of hetero-structure body-tied Ge FinFET using retrograde-well implantation

In this work, we investigated the influence of retrograde-well implantation on hetero-structure body-tied germanium (Ge) FinFET [1]. Using structural engineering, the retrograde well was fabricated prior to Ge epitaxy, which could avoid the activated temperature of dopant in Si substrate. With optimizing the implant condition, the p-Ge/n-Si hetero-structure junction exhibited high I
_ON
/I
_OFF
ratio and lower junction leakage (4 × 10
^-3
μA/cm
²
). Furthermore, we also make a comparison of planar and mesa junction structures, mesa junction exhibited lower junction leakage (6× 10
^-6
μA/cm
²
) as compared with the planar one mentioned before, which could be attributed to improvement in peripheral leakage due to dislocation within Ge and Si. Comparing the difference between retrograde-well and implant-free Ge FinFETs, the drain induced barrier lowering (DIBL) was considerably improved by 50 %. Our retrograde-well Ge FinFET exhibited a high I
_ON
/I
_OFF
ratio ~ 8×10
³
(I
_S
) than the conventional Ge FinFET (I
_ON
/I
_OFF
~2×10
³
).