Influence of substrate temperature on atomic layer growth and properties of HfO2 thin films

Aarik, Jaan; Aidla, Aleks; Kiisler, Alma‐Asta; Uustare, Teet; Sammelselg, Väinö

doi:10.1016/s0040-6090(98)01356-x

Cited by 283 publications

(162 citation statements)

References 15 publications

Supporting

Mentioning

150

Contrasting

Order By: Relevance

“…Both phases may be present, as the peaks could overlap in our XRD spectra; additional study is required to determine which phase is present. Our results are consistent with the results of Aarik et al, 29 who observed an orthorhombic phase in ALD HfO 2 films grown at 500°C. Ritala et al 30 also observed weak peaks at the same position of 2 ϭ30.4°.…”

Section: Methodssupporting

confidence: 93%

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

Gong

Wilk³

et al. 2003

Journal of Applied Physics

166

View full text Add to dashboard Cite

We report the effects of annealing on the morphology and crystallization kinetics for the high-gate dielectric replacement candidate hafnium oxide (HfO 2 ). HfO 2 films were grown by atomic layer deposition ͑ALD͒ on thermal and chemical SiO 2 underlayers. High-sensitivity x-ray diffractometry shows that the as-deposited ALD HfO 2 films on thermal oxide are polycrystalline, containing both monoclinic and either tetragonal or orthorhombic phases with an average grain size of ϳ8.0 nm. Transmission electron microscopy shows a columnar grain structure. The monoclinic phase predominates as the annealing temperature and time increase, with the grain size reaching ϳ11.0 nm after annealing at 900°C for 24 h. The crystallized fraction of the film has a strong dependence on annealing temperature but not annealing time, indicating thermally activated grain growth. As-deposited ALD HfO 2 films on chemical oxide underlayers are amorphous, but show strong signatures of ordering at a subnanometer level in Z-contrast scanning transmission electron microscopy and fluctuation electron microscopy. These films show the same crystallization kinetics as the films on thermal oxide upon annealing.

show abstract

Section: Methodssupporting

confidence: 93%

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

Gong

Wilk³

et al. 2003

Journal of Applied Physics

166

View full text Add to dashboard Cite

show abstract

“…14,15,18 However, some groups observed the peak corresponding to the ͑111͒ surface as the most intense peak along with that of the ͑001͒ face. 4,16 This can be explained if the ͑111͒ and ͑111͒ surfaces are ascribed as the thermodynamically favored surfaces while the ͑001͒ face could correspond to the kinetically favored surface, We predict a surface stability order for the surfaces we consider very similar to that predicted for the ZrO 2 surface. with a few exceptions.…”

Section: First-principles Calculations Of Structural¼ Physical Reviewsupporting

confidence: 60%

“…[1][2][3][4] Hafnium dioxide ͑HfO 2 ͒ has emerged as an excellent candidate due to its relatively high dielectric constant, wide band gap and stability on Si. The thermal stability of high-k materials in direct contact with Si and SiO 2 has become a key criterion in selecting suitable high-k choices.…”

Section: Introductionmentioning

confidence: 99%

“…13 The structure of as-deposited HfO 2 films is not yet fully resolved. For instance, various experimental studies found that HfO 2 films deposited by ALD at 300°C using HfCl 4 and H 2 O as precursors are polycrystalline, and mainly consist of the monoclinic phase with the ͑111͒ surface exhibited as the main growth face. 14,15 Upon annealing the intensities of the monoclinic peaks increase in the x-ray diffraction ͑XRD͒ spectra with the ͑111͒ and ͑111͒ monoclinic surfaces primarily populated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

First-principles calculations of structural and electronic properties of monoclinic hafnia surfaces

2006

View full text Add to dashboard Cite

We have carried out a systematic theoretical study of the surfaces of monoclinic hafnia ͑HfO 2 ͒ using plane waves and density functional theory based on the generalized gradient approximation. The fully relaxed structures of the bulk phases of HfO 2 are found to be in excellent agreement with experimental data, the monoclinic phase being the most stable. Simulations of the monoclinic phase surfaces indicate a large relaxation which reduces the total surface energy of all nine faces considered by between 23% and 36%, with a strong correlation between the unrelaxed and relaxed surface energies. Our calculations predict that the ͑111͒ and ͑111͒ faces of the monoclinic phase have the lowest surface energies and are hence the most stable faces. An analysis of the total and partial electronic density of states of bulk monoclinic HfO 2 reveals that the outer valence band significantly mixes the O 2p and Hf 5d atomic states indicating some covalency of the Hf-O bonds. The total density and partial density of states of the monoclinic surfaces exhibit a surface state corresponding to the surface O 2s states in the inner valence band region.

show abstract

“…This temperature range is close to the lowest temperature at which ALD of HfO 2 had been deposited from HfCl 4 [16,20]. At somewhat lower temperatures, unlimited condensation of HfCl 4 can take place on the substrate surface, as the lowest temperatures which ensure sufficient evaporation rates of HfCl 4 for ALD range from 130 to 150°C [17][18][19][20][21][22]. Second, 10-30 nm thick films were grown in a two-step process: the growth was initiated at 170°C, then after applying 10 ALD cycles the temperature was increased to 300°C and the growth was completed applying 100-300 cycles.…”

Section: Methodsmentioning

confidence: 65%

Atomic layer deposition of HfO2 on graphene from HfCl4 and H2O

Alles¹,

Aarik

Aidla

et al. 2011

Open Physics

View full text Add to dashboard Cite

Abstract:Atomic layer deposition of HfO 2 on unmodified graphene from HfCl 4 and H 2 O was investigated. Surface RMS roughness down to 0.5 nm was obtained for amorphous, 30 nm thick hafnia film grown at 180°C. HfO 2 was also deposited in a two-step temperature process where the initial growth of about 1 nm at 170°C was continued up to 10-30 nm at 300°C. This process yielded uniform, monoclinic HfO 2 films with RMS roughness of 1.7 nm for 10-12 nm thick films and 2.5 nm for 30 nm thick films. Raman spectroscopy studies revealed that the deposition process caused compressive biaxial strain in graphene, whereas no extra defects were generated. An 11 nm thick HfO 2 film deposited onto bilayer graphene reduced the electron mobility by less than 10% at the Dirac point and by 30-40% far away from it.PACS (2008)

show abstract

Influence of substrate temperature on atomic layer growth and properties of HfO2 thin films

Cited by 283 publications

References 15 publications

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

First-principles calculations of structural and electronic properties of monoclinic hafnia surfaces

Atomic layer deposition of HfO2 on graphene from HfCl4 and H2O

Contact Info

Product

Resources

About