Interface Trap Density Reduction Due to AlGeO Interfacial Layer Formation by Al Capping on Al2O3/GeOx/Ge Stack

Al electrode on Al
₂
O
₃
/GeO
_x
/Ge dielectrics stack has smaller interface trap density than Pt electrode due to the AlGeO formation at the interface. The AlGeO interfacial layer (IL) is formed during Al deposition. Pt electrode deposition after Al capping/removal process also exhibits the low interface trap density behavior. The increasing Al electrode area decreases interface trap density, indicating the AlGeO passivation is only effective underneath Al electrode. AlGeO layer can effectively passivate Ge with scaled GeO
_x
and Al
₂
O
₃
thickness. The peak hole mobility in Ge p-MOSFETs with AlGeO IL is 277 cm
²
/V · s.