Ge n+/p Junctions With High ON-to-OFF Current Ratio by Surface Passivation

The large junction leakage current in Ge CMOS is one of the most critical issues of our time. If the Ge surface is not well passivated, the surface leakage current may dominate. In this letter, thanks to the well-passivated surface by 10%-yttrium-doped GeO
₂
(YGO), Ge n
⁺
/p junctions showed much lower leakage than the SiO
₂
-passivated ones and an ON-to-OFF current ratio more than 3 × 10
⁶
at 1 V was achieved. Our result indicates that the high junction leakage current so far reported may not be intrinsic, and further reduction of the leakage current may be possible in Ge n
⁺
/p junctions.