Biaxial texture development in aluminum nitride layers during off-axis sputter deposition

Deng, Ruopeng; Muralt, Paul; Gall, Daniel

doi:10.1116/1.4732129

Cited by 27 publications

(15 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies already discussed a lot about the characterization of high quality AlN and AlScN: typically, such films would have pebble‐like surface morphology and homogeneous columnar structure can be observed in cross‐section. Additionally, 000 l ( l = 2, 4, 6) reflections in XRD 2 θ / θ scan and low rocking curve FWHM values indicate high degree of c ‐axis orientation.…”

Section: Discussionmentioning

confidence: 99%

Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Reusch

Kurz

et al. 2017

Physica Status Solidi (a)

View full text Add to dashboard Cite

Reactive pulsed DC magnetron co‐sputtering is used to grow piezoelectric aluminum nitride (AlN) and aluminum scandium nitride (AlScN) thin films on Si(001) substrates. By using grazing incidence X‐ray diffraction (GIXRD), scanning electron microscopy (SEM), and piezoresponse force microscopy (PFM), we investigate how the microstructure and the presence of misoriented grains affect the piezoelectric properties of the material. N2 concentration and target‐to‐substrate distance are finely tuned to achieve thin films without misoriented grains, resulting in Al0.87Sc0.13N thin films with low roughness, high degree of c‐axis orientation, homogenous polarity, and piezoelectric coefficient d33 = −12.3 pC/N.

show abstract

Section: Discussionmentioning

confidence: 99%

Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Reusch

Kurz

et al. 2017

Physica Status Solidi (a)

View full text Add to dashboard Cite

show abstract

“…Double-side polished 10×10×0.5 mm 3 magnesium oxide MgO(001) substrates were ultrasonically cleaned in trichloroethylene, acetone and isopropyl alcohol for 15 min each, rinsed in de-ionized water, blown dry with dry nitrogen, mounted onto a substrate holder using silver paint, inserted into the deposition system, and degassed for 1 hour at 1000 °C. 14,66 Prior to deposition, the 5-cm-diameter nominally 99.99% pure Sc target was sputter-cleaned for 10 min in a 99.999% pure N 2 /Ar gas using a protective disc preventing the Heaven's formulas, 68 and treating absorption in the substrate and the multiple light paths associated with reflection at the backside of the substrate by incoherent addition. All data analyses assumed normal incident light for reflection instead of the experimental 6°, which causes negligible (<1%) errors in the presented data.…”

Section: A Sample Preparation and Analysismentioning

confidence: 99%

Optical and transport measurement and first-principles determination of the ScN band gap

et al. 2015

Self Cite

View full text Add to dashboard Cite

The electronic structure of scandium nitride is determined by combining results from optical and electronic transport measurements with first-principles calculations. Hybrid functional (HSE06) calculations indicate a 0.92 eV indirect Γ-to-X band gap and direct transition energies of 2.02 and 3.75 eV at Γ-and X-points, respectively, while G o W o and GW o methods suggest 0.44-0.74 eV higher gap values. Epitaxial ScN(001) layers deposited on MgO(001) substrates by reactive sputtering exhibit degenerate n-type semiconductor properties with a temperature-independent electron density that is varied from N = 1.12-12.8×10 20 cm -3 using F impurity doping. The direct optical gap increases linearly with N from 2.18 to 2.70 eV, due to a Burstein-Moss effect. This strong dependence on N is likely the cause for the large range (2.03-3.2 eV) of previously reported gap values. However, here extrapolation to N = 0 yields 2.07±0.05 eV for the direct X-point transition of intrinsic ScN. A reflection peak at 3.80±0.02 eV is independent of N and in perfect agreement with the HSE06-predicted peak at 3.79 eV, associated with a high joint-density of states near the Γ-point. The electron mobility at 4 K is 100±30 cm 2 /Vs and decreases with temperature due to scattering at polar optical phonons with characteristic frequencies that decrease from 620 to 440±30 cm -1 with increasing N, due to free carrier screening. The transport and density-of-states electron effective mass, determined from measured intra and inter band transitions, respectively, are 0.40±0.02 m o and 0.33±0.02 m o , in good agreement with the firstprinciples predictions of m tr = 0.33±0.05 m o and m DOS = 0.43±0.05 m o . The ScN refractive index increases with increasing hν = 1.0-2.0 eV from 2.6-3.1 based on optical measurements and from 2.8-3.2 based on the calculated dielectric function. An overall comparison of experiment and simulation indicates (i) an overestimation of band gaps by GW methods but (ii) excellent agreement with a deviation of ≤0.05 eV for the hybrid functional and (iii) a value for the fundamental indirect gap of ScN of 0.92±0.05 eV.

show abstract

“…9,19-21 Double in-plane alignment has only been reported by Deng et al 22 for AlN films grown at a vapor flux incidence angle of 45 which changes into a single in-plane alignment for larger vapor incident angles. The reason for the discrepancy between experimental data and model predictions is still unknown.…”

mentioning

confidence: 98%

Double in-plane alignment in biaxially textured thin films

Elofsson

Saraiva

Boyd

et al. 2014

Applied Physics Letters

View full text Add to dashboard Cite

The scientific interest and technological relevance of biaxially textured polycrystalline thin films stem from their microstructure that resembles that of single crystals. To explain the origin and predict the type of biaxial texture in off-normally deposited films, Mahieu et al. have developed an analytical model [S. Mahieu et al., Thin Solid Films 515, 1229 (2006)]. For certain materials, this model predicts the occurrence of a double in-plane alignment, however, experimentally only a single in-plane alignment has been observed and the reason for this discrepancy is still unknown. The model calculates the resulting in-plane alignment by considering the growth of faceted grains with an out-of-plane orientation that corresponds to the predominant film out-of-plane texture. This approach overlooks the fact that in vapor condensation experiments where growth kinetics is limited and only surface diffusion is active, out-of-plane orientation selection is random during grain nucleation and happens only upon grain impingement. Here, we compile and implement an experiment that is consistent with the key assumptions set forth by the in-plane orientation selection model by Mahieu et al.; a Cr film is grown off-normally on a fiber textured Ti epilayer to pre-determine the out-of-plane orientation and only allow for competitive growth with respect to the in-plane alignment. Our results show unambiguously a biaxially textured Cr (110) film that possesses a double in-plane alignment, in agreement with predictions of the in-plane selection model. Thus, a long standing discrepancy in the literature is resolved, paving the way towards more accurate theoretical descriptions and hence knowledge-based control of microstructure evolution in biaxially textured thin films.

Funding Agencies|Linkoping University

show abstract

Biaxial texture development in aluminum nitride layers during off-axis sputter deposition

Cited by 27 publications

References 53 publications

Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Optical and transport measurement and first-principles determination of the ScN band gap

Double in-plane alignment in biaxially textured thin films

Contact Info

Product

Resources

About