the effects of YON interfacial passivation layer (IPL) on the interfacial and electrical properties of Ge metal-oxide-semiconductor (MOS) capacitor with HfO

2

gate dielectric are investigated.The YON IPL is fabricated by two different approaches:one is to sputter Y

2

O

3

target in Ar+N

2

to directly form YON

and another is to sputter Y target in Ar+N

2

to deposit YN first and then perform

annealing in N

2

+O

2

to convert YN to YON.Experimental results and XPS analyses indicate that the latter could suppress formation of the Ge oxides at/near the YON/Ge interface more efficiently to achieve more excellent interfacial and electrical properties as compared to the former

since the YN can absorb oxygen diffused to the interface to form YON prior to the Ge surface.As a result

small capacitance equivalent thickness (1.65 nm)

high

k

value (18.9)

low interface-state density (7.7910

11

cm

-2

eV

-1

) and equivalent oxide-charge density (-3.5410

12

cm

-2

)

small gate leakage current density (2.7410

-4

A/cm

2

at

V

g

=

V

fb

+1 V) and good high-field stressing reliability have been obtained.