Low-temperature atomic layer epitaxy of AlN ultrathin films by layer-by-layer, in-situ atomic layer annealing

Shih, Huan-Yu; Lee, Wei-Hao; Kao, Wei-Chung; Chuang, Yung-Chuan; Lin, Ray–Ming; Lin, Hung-Yin; Shiojiri, Makoto; Chen, Miin-Jang

doi:10.1038/srep39717

Cited by 91 publications

(66 citation statements)

References 35 publications

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“…Due to the relatively low temperature, the remaining N–H bonds from N 2 H 4 are dominant after ligand exchange with TMA, resulting in the lower GPC results [ 31 ]. The R.I. of AlN film deposited at 350 °C is 1.98, which is close to the reported values of high-quality AlN films [ 32 , 33 , 34 ].…”

Section: Resultssupporting

confidence: 87%

Low Temperature Thermal Atomic Layer Deposition of Aluminum Nitride Using Hydrazine as the Nitrogen Source

Jung

Hwang

et al. 2020

Materials

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Aluminum nitride (AlN) thin films were grown using thermal atomic layer deposition in the temperature range of 175–350 °C. The thin films were deposited using trimethyl aluminum (TMA) and hydrazine (N2H4) as a metal precursor and nitrogen source, respectively. Highly reactive N2H4, compared to its conventionally used counterpart, ammonia (NH3), provides a higher growth per cycle (GPC), which is approximately 2.3 times higher at a deposition temperature of 300 °C and, also exhibits a low impurity concentration in as-deposited films. Low temperature AlN films deposited at 225 °C with a capping layer had an Al to N composition ratio of 1:1.1, a close to ideal composition ratio, with a low oxygen content (7.5%) while exhibiting a GPC of 0.16 nm/cycle. We suggest that N2H4 as a replacement for NH3 is a good alternative due to its stringent thermal budget.

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Section: Resultssupporting

confidence: 87%

Low Temperature Thermal Atomic Layer Deposition of Aluminum Nitride Using Hydrazine as the Nitrogen Source

Jung

Hwang

et al. 2020

Materials

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“…The presented GIXRD results are also supported by the density, roughness, and Al/N ratio results which were higher for films showing the lowest FWHM thus indicating a higher degree of crystallinity (especially the PA_25V and the PA_300C). In previous PEALD AlN studies, the degree of crystallinity has been shown to extend from amorphous 7,24 to polycrystalline 8,26 and even to the epitaxial grade [the (002) rocking curve being 144 arcsec] 44 depending on the process parameters, chosen substrate, surface treatment, and PEALD reactor setup. These aspects affect the impurity levels which in turn are known to affect crystallinity.…”

Section: Crystallinitymentioning

confidence: 99%

Comparison of mechanical properties and composition of magnetron sputter and plasma enhanced atomic layer deposition aluminum nitride films

Sippola

Perros

Ylivaara

et al. 2018

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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A comparative study of mechanical properties and elemental and structural composition was made for aluminum nitride thin films deposited with reactive magnetron sputtering and plasma enhanced atomic layer deposition (PEALD). The sputtered films were deposited on Si (100), Mo (110), and Al (111) oriented substrates to study the effect of substrate texture on film properties. For the PEALD trimethylaluminum-ammonia films, the effects of process parameters, such as temperature, bias voltage, and plasma gas (ammonia versus N 2 /H 2 ), on the AlN properties were studied. All the AlN films had a nominal thickness of 100 nm. Time-of-flight elastic recoil detection analysis showed the sputtered films to have lower impurity concentration with an Al/N ratio of 0.95, while the Al/N ratio for the PEALD films was 0.81-0.90. The mass densities were ∼3.10 and ∼2.70 g/cm 3 for sputtered and PEALD AlN, respectively. The sputtered films were found to have higher degrees of preferential crystallinity, whereas the PEALD films were more polycrystalline as determined by x-ray diffraction. Nanoindentation experiments showed the elastic modulus and hardness to be 250 and 22 GPa, respectively, for sputtered AlN on the (110) substrate, whereas with PEALD AlN, values of 180 and 19 GPa, respectively, were obtained. The sputtered films were under tensile residual stress (61-421 MPa), whereas the PEALD films had a residual stress ranging from tensile to compressive (846 to −47 MPa), and high plasma bias resulted in compressive films. The adhesion of both films was good on Si, although sputtered films showed more inconsistent critical load behavior. Also, the substrate underneath the sputtered AlN did not withstand high wear forces as with the PEALD AlN. The coefficient of friction was determined to be ∼0.2 for both AlN types, and their wear characteristics were almost identical. Published by the AVS.

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“…For application in nanoelectronics, it is essential to have atomic precision in materials manufacturing. Over the last decades ALD proved to be a relatively affordable method with high scalability and repeatability while also providing the necessary precision of the atomic layer for films fabrication at the nanoscale level [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Aluminum Nitride Nanofilms by Atomic Layer Deposition Using Alternative Precursors Hydrazinium Chloride and Triisobutylaluminum

et al. 2020

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The aim of this study is motivated by the pursuit to investigate the performance of new and as yet untested precursors such as hydrazinium chloride (N2H5Cl) and triisobutylaluminum Al(C4H9)3 in the AlN atomic layer deposition (ALD) process as well as to study effects of successive annealing on the quality of the resulting layer. Both precursors are significantly cheaper than their conventional counterparts while also being widely available and can boast easy handling. Furthermore, Al(C4H9)3 being a rather large molecule might promote steric hindrance and prevent formation of undesired hydrogen bonds. Chemical analysis is provided by X-ray photoelectron spectroscopy (XPS) and secondary-ion mass spectrometry (SIMS) techniques; surface morphology was studied using atomic force microscopy (AFM). Chlorine containing precursors such as AlCl3 are usually avoided in ALD process due to the risk of chamber contamination. However, experimental data of this study demonstrated that the use of N2H5Cl does not result in chlorine contamination due to the fact that temperature needed for HCl molecules to become reactive cannot be reached within the AlN ALD window (200–350 °C). No amount of chlorine was detected even by the most sensitive techniques such as SIMS, meaning it is fully removed out of the chamber during purge stages. A part of the obtained samples was subjected to annealing (1350 °C) to study effects of high-temperature processing in nitrogen atmosphere, the comparisons with unprocessed samples are provided.

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Low-temperature atomic layer epitaxy of AlN ultrathin films by layer-by-layer, in-situ atomic layer annealing

Cited by 91 publications

References 35 publications

Low Temperature Thermal Atomic Layer Deposition of Aluminum Nitride Using Hydrazine as the Nitrogen Source

Low Temperature Thermal Atomic Layer Deposition of Aluminum Nitride Using Hydrazine as the Nitrogen Source

Comparison of mechanical properties and composition of magnetron sputter and plasma enhanced atomic layer deposition aluminum nitride films

Aluminum Nitride Nanofilms by Atomic Layer Deposition Using Alternative Precursors Hydrazinium Chloride and Triisobutylaluminum

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