High resolution electron microscopy studies of native oxide on silicon

Mazur, J.H.; Grónsky, R.; Washburn, J.

doi:10.1201/9781003069614-12

Cited by 5 publications

(2 citation statements)

References 1 publication

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“…The thickness values obtained are consistent with many studies using the same (Ellipsometry and XPS) ,− or other (Atom Probe and Transmission Electron Microscopy) − techniques. As shown in Figure , t is included in the [0.75, 2.2] nm interval (see dotted lines), similar to the range obtained in this work.…”

Section: Discussionsupporting

confidence: 88%

Native Silicon Oxide Properties Determined by Doping

Della Ciana,

Kovtun,

Summonte

et al. 2023

Langmuir

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The physico-chemical properties of native oxide layers, spontaneously forming on crystalline Si wafers in air, can be strictly correlated to the dopant type and doping level. In particular, our investigations focused on oxide layers formed upon air exposure in a clean room after Si wafer production, with dopant concentration levels from ≈10 13 to ≈10 19 cm −3 . In order to determine these correlations, we studied the surface, the oxide bulk, and its interface with Si. The surface was investigated using the contact angle, thermal desorption, and atomic force microscopy measurements which provided information on surface energy, cleanliness, and morphology, respectively. Thickness was measured with ellipsometry and chemical composition with X-ray photoemission spectroscopy. Electrostatic charges within the oxide layer and at the Si interface were studied with Kelvin probe microscopy. Some properties such as thickness, showed an abrupt change, while others, including silanol concentration and Si intermediate-oxidation states, presented maxima at a critical doping concentration of ≈2.1 × 10 15 cm −3 . Additionally, two electrostatic contributions were found to originate from silanols present on the surface and the net charge distributed within the oxide layer. Lastly, surface roughness was also found to depend upon dopant concentration, showing a minimum at the same critical dopant concentration. These findings were reproduced for oxide layers regrown in a clean room after chemical etching of the native ones.

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Section: Discussionsupporting

confidence: 88%

Native Silicon Oxide Properties Determined by Doping

Della Ciana,

Kovtun,

Summonte

et al. 2023

Langmuir

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“…100 nm thick Cu film was deposited on Si using direct current (DC) magnetron sputtering. It should be noted that although Si substrate was cleaned sequentially using Piranha and dilute HF (1 part of HF in the 50 parts of water) solutions, the native oxide layer formed on Si during subsequent storage (approximately one week) before the deposition of the thin film was not removed, and hence a thin layer of SiO 2 (∼3-4 nm [41,42]) is expected to be there in between Cu and Si. Following the thin film deposition, samples were annealed in a high vacuum furnace, operating at 10 −6 mbar, at 600 °C for 2 h. The ramp rate used for heating was ∼11 °C min −1 and subsequently, the samples were furnace cooled to room temperature.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Stability of Cu-islands formed on Si substrate via ‘dewetting’ under subsequent thermal cycling

Sonawane

Kumar

2021

Nanotechnology

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Very thin metallic films deposited on a substrate often dewet upon thermal exposure, forming discrete islands of micrometer and nanometer-sized metal particles. Herein, Cu islands on Si substrate, which were formed due to agglomeration (or ‘dewetting’) of Cu thin film at 600 °C, were exposed to thermal cycling, and the ensuing evolution in their morphology was monitored. Thermal cycling was performed between either −25 °C and 150 °C or 25 °C and 400 °C, using different heating and cooling rates. With faster heating-cooling rates, a change in the shape and size of the Cu islands was observed, whereas a slow heating-cooling rate did not induce noticeable effect on their morphology. Furthermore, the formation of new nano- and micro-sized particles, probably through the dewetting of the ultra-thin layer of Cu that was left intact during the initial agglomeration treatment, was observed during the thermal cycling performed at fast rates up to 400 °C. Finite element analysis, incorporating Anand’s viscoplasticity model, revealed the existence of high strain energy density in the vicinity of the particle-Si interface when the thermal cycling is carried at a faster ramp rate, suggesting the pivotal role of thermal stresses, in addition to the maximum temperature, in controlling the morphology of the Cu particles and the dewetting of the residual ultra-thin layer of Cu on Si.

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