Abstract
(
B
0.5−x
Si
x
)
N
0.5
films
(0⩽x⩽0.5)
were prepared by dual ion beam deposition. Buffer layers were added to improve the film adhesion. The film structure was characterized by x-ray photoelectron spectroscopy, infrared absorption, and x-ray diffraction. The hardness and elastic modulus were measured by a nanoindenter. The
I–V
curves of the
Ti
/(
B
0.5−x
Si
x
)
N
0.5
/buffer
/p-
Si/Ti
diodes were investigated. The films are composites of cubic-boron nitride (
c
-BN),
h
-BN, and Si–N. When
x=0,
the film contains 70–75 vol %
c
-BN and has a hardness ≈38 GPa, but peels off quickly from the substrate after exposure to air. When
x
increases to 0.013, a small amount of Si–N phase is formed, which serves to release part of the internal stress without affecting the volume fraction of
c
-BN or the mechanical strength, and good adhesion is achieved. For higher Si content
(0.013<x⩽0.067),
the
c
-BN phase is disrupted with simultaneous replacement by
h
-BN. Rapid drops in the hardness and elastic modulus follow. When the Si content continues to increase (0.067 to 0.51), the fraction of the
h-
BN
phase decreases progressively with simultaneous replacement by Si–N. Both the hardness and elastic modulus rise and approach those of silicon nitride.
I–V
curves of
Ti
/(
B
0.5−x
Si
x
)
N
0.5
/
buffer
/p-
Si/Ti
diodes show a strong rectifying effect, which becomes less pronounced when
x
is larger.