Silicon nitride (SiN

x

) film with excellent quality in both passivation and antireflection was deposited by mid-frequency (MF) magnetron sputtering process. The structure

optical property and other relevant performances of the thin films were investigated. The results show that

in the range of 300-1 100 nm

the average reflection of the textured silicon decreased from 14.86% to 5.50% and 6.58% respectively by applying two different single layer of SiNx films. The average reflection further decreased to a value of 4.03% when a multilayer of m-SiN

x

+ SiO

x

N

y

film was applied. Meanwhile

a hydrogen doped silicon nitride (SiN

x

∶H) film was prepared for the passivation purpose. Based on the parameter optimization

two series of the composite films including SiN

x

∶H (15 nm in thickness) + SiN

x

+ SiO

x

N

y

and SiN

x

∶H (30 nm in thickness) + SiN

x

+ SiO

x

N

y

were prepared. The average reflections of the composite films reached at 5.88% and 5.43%

respectively. The films were then applied to the crystalline silicon solar cells

an open circuit voltage of 575 mV were achieved

indicating the composite film with a good passivation property.