CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

[150,151] This is a unique feature for hafnium nitride considering that no such effect is observed
in hafnium metal, hafnium carbide or hafnium oxide.[152,153] The peak shift of Hf4f7/2 from
16.4ev to 15.1ev also indicated the presence of hafnium nitride phase after removal of the top
layers. Apparently this phase is hafnium rich due to the incorporation of C and O.
X-ray diffraction study shows that all the as deposited thin films on both Si(100) or
SiO2/Si are amorphous without any crystalline features. The only X-ray diffraction signals are
from the single crystal silicon substrate. Cross sectional view by SEM and TEM and surface
morphology by AFM for a multilayer sample of HfNxCy/SiO2 Si prepared at 250˚C and 100W
are shown in Fig.35 (a), (b) and (c) respectively. The SEM image shows the clear layered
structure and a dense HfNxCy film around 80 nm depostied on SiO2/Si. The HRTEM image
showed the interface between HfNxCy and that between Si and SiO2. Clear lattice fringes from
(100) planes of the Si single crystal can be observed. Selected area diffraction has proved that
there is no crystalline feature for the SiO2 and HfNxCy layers, as measured by XRD. The gradual
contrast change in the interface indicates a gradual mass density change, which might be due to
small amount of interdiffusion in a thickness range of 1~2 nm. The RMS surface roughness was
measured to be 0.8nm for a scanning area of 1 μm 2 .
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