TY - JOUR
T1 - Hafnium diboride thin films by chemical vapor deposition from a single source precursor
AU - Jayaraman, Sreenivas
AU - Yang, Yu
AU - Kim, Do Young
AU - Girolami, Gregory S.
AU - Abelson, John R.
N1 - Funding Information:
The authors are grateful to the National Science Foundation for support of this research under Grant Nos. NSF CH-00-76061, NSF DMR-03-54060, and NSF DMR-03-15428. Compositional and structural analyses of the films were carried out in the Center for Microanalysis of Materials, University of Illinois, which is partially supported by the U.S. Department of Energy under Grant No. DEFG02-91-ER45439. FIG. 1. Log of film growth rate (open squares) and hafnium atomic density from RBS (open triangles) versus inverse absolute temperature. The data from the epitaxial film are indicated by the solid square and solid triangle. The temperature axis is labeled in centigrade for convenience. FIG. 2. SEM fracture cross sections of the Hf B 2 films on silicon substrates deposited at (a) 250 ° C ; (b) 400 ° C ; (c) 700 ° C . FIG. 3. XRD profile of Hf B 2 at different deposition temperatures. Boric acid, B [ O H ] 3 crystals form when surface boron oxide adsorbs moisture. FIG. 4. Precursor cracking pattern in the mass spectrometer. FIG. 5. Precursor intensity variation at m ∕ z = 208 during TPR experiments: (a) precursor intensity versus substrate temperature; (b) natural logarithm of precursor consumed versus inverse absolute temperature. FIG. 6. (a) Boron 2 p peak in the XPS; (b) Hf 5 p 3 ∕ 2 peak in the XPS. The top panel in both the figures is the signal from the surface and the bottom panel is the signal from the bulk. The surface signal contains contributions from both the hafnium boride and the respective oxide phases. FIG. 7. Apparent B ∕ Hf atomic ratio in the film surface (squares) and bulk (triangles) from XPS. The data points at 900 ° C represent the epitaxial film. FIG. 8. Film resistivity from four point probe measurements plotted versus deposition temperature. FIG. 9. RBS from a multilayer sample ( 30 nm ) Cu ∕ ( 12 nm ) Hf B 2 ∕ Si , as-deposited (top), vacuum-annealed at 600 ° C for 30 min (middle) and vacuum annealed at 700 ° C for 30 min (bottom). FIG. 10. Conformal nature of the growth process (a) 2.5:1 depth-width aspect ratio trench features coated at 200 ° C ; (b) 19:1 aspect ratio trench coated at the reaction onset temperature < 200 ° C .
PY - 2005/11
Y1 - 2005/11
N2 - High quality, stoichiometric thin films of hafnium diboride are deposited by chemical vapor deposition from the precursor Hf [B H4] 4 at deposition temperatures as low as 200°C. An activation energy of 0.43 eV (41 kJmol) is obtained for the overall process as monitored by temperature programmed reaction studies. Films deposited at low temperatures (<500°C) are structurally amorphous to x-ray diffraction; a 12 nm thick film is sufficient to prevent copper diffusion into silicon during a 600°C anneal for 30 min. Films deposited above 500°C are crystalline, but have a columnar microstructure with low density. All the films are metallic, but the low temperature amorphous films have the lowest resistivity ∼440 μΩ cm. The process is also highly conformal, e.g., a 65 nm wide trench with a 19:1 depth-width aspect ratio was coated uniformly.
AB - High quality, stoichiometric thin films of hafnium diboride are deposited by chemical vapor deposition from the precursor Hf [B H4] 4 at deposition temperatures as low as 200°C. An activation energy of 0.43 eV (41 kJmol) is obtained for the overall process as monitored by temperature programmed reaction studies. Films deposited at low temperatures (<500°C) are structurally amorphous to x-ray diffraction; a 12 nm thick film is sufficient to prevent copper diffusion into silicon during a 600°C anneal for 30 min. Films deposited above 500°C are crystalline, but have a columnar microstructure with low density. All the films are metallic, but the low temperature amorphous films have the lowest resistivity ∼440 μΩ cm. The process is also highly conformal, e.g., a 65 nm wide trench with a 19:1 depth-width aspect ratio was coated uniformly.
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U2 - 10.1116/1.2049307
DO - 10.1116/1.2049307
M3 - Article
AN - SCOPUS:31044452458
SN - 0734-2101
VL - 23
SP - 1619
EP - 1625
JO - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
JF - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
IS - 6
ER -