Characterization of Atomic Layer Deposition using X-Ray Reflectometry

In this work are presented the results obtained from the deposition ofCd1-xZnxTe nanolayers using as precursor the vapours of the elementsZn, Te, and a mixture of Cd and Zn on GaAs and GaSb (001) substrates by Atomic Layer Deposition technique (ALD), which allows the deposition of layers of nanometric dimensions. At each exposure of the growth surface to the of cation or anion precursors vapours, this surface is saturated. Therefore, it is considered that the process is self-regulated. The ZnTe layers were grown in a wide range of temperatures; however, ZnTe nanolayers with a shiny mirror-like surface could be grown at temperatures between 370 and 410oC. Temperatures higher than 400oC were necessary for the CdTe growth. The layers of the Cd1-xZnxTe ternary alloy were deposited at temperature range of 400 and 425oC. The grown nanofilms were characterized by Raman spectroscopy and high-resolution X-ray diffraction. The Raman spectrumshows the peak corresponding to LO-ZnTe at 208 cm-1, which is weak and is slightly redshifted in comparison with the reported for the bulk ZnTe. For the case of the CdTe nanolayers, Raman spectrum presents the LO-CdTe peak, which is indicative of the successfully growth of the nanolayers, its weakness and its slight redshifted in comparison with the reported for the bulk CdTe can be related with the nanometric characteristic of this layer. The performed high resolution X-ray diffraction measurements allowed to study some importantcharacteristics, as the crystallinity of the grown layers. Additionally, the performed HR-XRD measurements suggest that the crystalline quality have dependence with the growth temperature.

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Physical characterization of hafnium aluminates dielectrics deposited by atomic layer deposition

Journal of Integrated Circuits and Systems ◽

10.29292/jics.v10i1.405 ◽

2015 ◽

Vol 10 (1) ◽

pp. 49-58

Author(s):

Danilo R. Huanca ◽

V. Christiano ◽

C. Adelmann ◽

Patrick Verdonck ◽

Sebastião G. Dos Santos Filho

Keyword(s):

Atomic Layer Deposition ◽

Chemical Elements ◽

Atomic Layer ◽

Homogeneous Distribution ◽

Gyration Radius ◽

Crystalline Phases ◽

X Ray ◽

Layer Deposition ◽

Scanning Electron

Hafnium aluminates films with 50 mol% of Hf were deposited onto Si(100) using atomic layer deposition. The films were annealed by RTP at 1000 oC for 60 s in pure N2 or N2+5%O2 and by LASER at 1200oC for 1ms in pure N2. Then, they were characterized by X-ray spectroscopies, ellipsometry, Rutherford backscattering and scanning electron microscopy. For thin films annealed by RTP in N2, phase separation takes place, promoting the formation of HfO2 and Al2.4 O3.6 crystalline phases. In contrast, the films annealed by LASER remain predominantly amorphous with crystalline facets of Al2.4O3.6. Also, non-homogeneous distribution of the chemical elements within the dielectrics gave rise to the formation of several regions which can be viewed as sub-layers, each of them with arbitrary electron density and thickness. As a result, Kratky curves pointed out to the coexistence of different features described by different gyration radius yielding GISAXS scattering profiles with polydispersive characteristics. Finally, the samples annealed by RTP were interpreted as agglomerates of spheroids with different sizes (1.1-2.2 nm) and with different crystalline phases whereas the samples annealed by LASER were interpreted as larger spheroids of crystalline Al2.4O3.6 (1.7-2.7nm) embedded in a matrix predominantly amorphous.

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