Effects of Nd content in Al thin films on hillock formation

Onishi, Takashi; Iwamura, Eiji; Takagi, Katsutoshi; Watanabe, Takashi

doi:10.1116/1.580745

Cited by 39 publications

(31 citation statements)

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“…12,13) Both values are at all temperatures less than that of aluminum. 12) According to the literature, 14,15) the precipitates Al 3 Sc and Al 4 Nd exists uniformly over the entire film and minor solutes Sc and Nd are dissolved in the -Al matrix for the Al-Sc and the Al-Nd thin film, respectively. Figure 5 reveals that the roughness of the Al-Sc alloy film is less than that of the Al-Nd alloy both before and after annealing, because the solubility of Sc in Al greatly exceeds that of Nd, and the melting point of the Al-Sc intermetallic compound exceeds that of Al-Nd.…”

Section: Microstructures Of Filmsmentioning

confidence: 99%

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Chen

Huang

2005

Mater. Trans.

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The interconnections among thin film transistor liquid crystal displays (TFT-LCDs) are laid on the films, made by the spotted coating method. This work studies the effect of heat-treatment, at temperatures from 523 K to 673 K, on the microstructure and physical properties of the deposited alloy thin films. The experimental results imply that, following heat treatment, the roughness of the aluminum-scandium (Al-Sc) alloy film is less than that of the aluminum-neodymium (Al-Nd) alloy, and the hillocks of the Al-Sc alloy film are lower. Accordingly, components are predicted to fail less often. The resistivity of the Al-Sc thin film is less than that of the Al-Nd thin film before it is thermally treated. Heat treatment reduces the resistivity of both, even though the reduced resistivity of Al-Nd exceeds the resistivity of the Al-Sc alloy film. Restated, the resistivity of the thermally stable Al-Sc thin film exceeds that of the Al-Nd thin film. Experimental results imply that the Al-Sc alloy is the more effective for making the driving circuit wires in the TFT-LCDs.

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Section: Microstructures Of Filmsmentioning

confidence: 99%

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Chen

Huang

2005

Mater. Trans.

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“…For most small displays, a stack of high purity aluminum film with molybdenum cap/underlayer can provide adequate resistance to hillock formation and meet resistivity requirement (<5 μΩcm). However, Al-Nd alloys are preferred in large displays because of its unique ability to offer adequate resistance to hillock formation and low resistivity [2][3][4] . The cost of Al-Nd alloy sputtering targets is quite high because of the expensive Nd and also the metallurgical processing steps used in the manufacturing of sputtering targets [5] .…”

Section: Introductionmentioning

confidence: 99%

“…Currently aluminum or Al-Nd binary alloy thin films are used in gate and source-drain applications in amorphous silicon based thin film transistor--liquid crystal displays (TFT-LCDs) [1][2][3][4] . For most small displays, a stack of high purity aluminum film with molybdenum cap/underlayer can provide adequate resistance to hillock formation and meet resistivity requirement (<5 μΩcm).…”

Section: Introductionmentioning

confidence: 99%

A combinatorial approach of developing alloy thin films using co-sputtering technique for displays

Sarkar¹,

Huang

Wang

et al. 2009

Sci. China Ser. E-Technol. Sci.

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In this study we have used a combinatorial approach for producing binary and ternary alloy thin film libraries using a lab-scale RF co-sputtering system. Initially we used two elemental sputtering targets, i.e. aluminum (Al) target and neodymium (Nd) target, to produce a film library of varying composition and successfully identified a suitable composition range (1.95-2.38 at% Nd) in which resistance to hillock formation and resistivity of the film spots were found to be satisfactory in annealed state (350℃, 30 min). In another case, in order to form ternary alloy composition library we have used two sputtering targets, i.e. an Al-0.5 at% Nd alloy target and an elemental Ni target. Though, co-sputtered Al-0.6 at% Nd-0.9 at% Ni alloy films showed satisfactory resistance to hillock formation and low resistivity after annealing, film deposited from a ternary alloy target with the same composition failed to show satisfactory resistance to hillock formation during annealing. In case of Al-0.6 at% Nd-0.9 at% Ni alloy target, 250 nm thick film showed poor resistance to hillock formation than the 500 nm thick film. This clearly showed thickness-dependent hillock performance of Al-0.6 at% Nd-0.9 at% Ni alloy. In this study it was found that, in addition to the process variables, metallurgical microstructure of the alloy sputtering targets had significant effect on the film properties which was not obvious from the results of films deposited using co-sputtering of the individual elemental targets.co-sputtering, thin films, aluminum alloys, displays

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“…As the size and resolution of thin film transistor liquid crystal displays (TFT-LCDs) increase, copper is becoming an attractive candidate for the gate and interconnect materials to replace Mo(W) and Al(Nd) 1,2) alloys. 3) Copper has been evaluated for use in TFT-LCDs gate electrodes, 4,5) and the Cu-based TFT production process includes formation of a Cu/Mo bilayer gate electrode using wet etching of a sputterdeposited Cu/Mo bilayer.…”

Section: Introductionmentioning

confidence: 99%

Growth of Ti-Based Interface Layer in Cu(Ti)/Glass Samples

et al. 2011

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Cu(Ti) alloy films with low-resistivity and excellent-adhesion have been successfully prepared on glass substrates. To gain further resistivity reduction and adhesion strength, growth of a Ti-based interface layer was investigated using Rutherford backscattering spectrometry (RBS) in the present study. Cu(0$5 at%Ti) alloy films were deposited on glass substrates and subsequently annealed in vacuum at 400$600 C for 0:5$24 h. Results were compared with those for samples on SiO 2 substrate previously obtained. Ti peaks were obtained in RBS spectra only at the interfaces for both Cu(Ti)/glass and Cu(Ti)/SiO 2 samples. Molar amounts of Ti atoms segregated to the interfaces (n) were estimated from Ti peak areas. The m values estimated from the slopes of the log n versus log t lines were almost similar for all the samples (m ¼ 0:10$0:12), suggesting that growth of the Ti-based interface layers was controlled by a similar mechanism. The activation energy of the Cu(Ti)/glass samples was similar to that of the Cu(Ti)/SiO 2 samples, while a pre-exponential factor (Z) of the Cu(Ti)/glass samples was approximately half of the value of the Cu(Ti)/SiO 2 samples. The Z value shows the frequency with which the Ti atoms meet oxygen in the glass substrates. Impurities in the glass substrates lowered the frequency. These factors lead to the conclusion that growth rate of the Ti-based interface layers on glass substrates was slower than that on SiO 2 . The Ti-based interface layer growth was also influenced by microstructure of Cu(Ti) alloy films formed on the glass substrates. Columnar grains in the Cu(Ti) alloy films were seen to enhance Ti segregation. However, an equiaxed zone above the interface retarded Ti diffusion to the interface, leading to lack of Ti atoms for the reaction.

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Effects of Nd content in Al thin films on hillock formation

Cited by 39 publications

References 0 publications

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

A combinatorial approach of developing alloy thin films using co-sputtering technique for displays

Growth of Ti-Based Interface Layer in Cu(Ti)/Glass Samples

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