Comparative Study on in-situ Ellipsometric Monitoring of III-Nitride Film Growth via Plasma-Enhanced Atomic Layer Deposition

2019 ◽  
Vol 28 (03n04) ◽  
pp. 1940020
Author(s):  
Adnan Mohammad ◽  
Deepa Shukla ◽  
Saidjafarzoda Ilhom ◽  
Brian Willis ◽  
Ali Kemal Okyay ◽  
...  

In this paper a comparative in-situ ellipsometric analysis is carried out on plasma-assisted ALD-grown III-nitride (AlN, GaN, and InN) films. The precursors used are TMA, TMG, and TMI for AlN, GaN, and InN respectively, while Ar is used as purge gas. For all of the films N2/H2/Ar plasma was used as the co-reactant. The work includes real-time in-situ monitored saturation curves, unit ALD cycle analysis, and >500 cycle film growth runs. In addition, the films are grown at different substrate temperatures to observe the impact of temperature not only on the growth rate but on how it influenced the precursor chemisorption, ligand removal, and nitrogen incorporation surface reactions. All three nitride films confirm fairly linear growth character. The growth rate per cycle (GPC) for each film is also measured with respect to rf-plasma power to obtain the surface saturation conditions during ALD growth. The real-time in-situ monitoring of the film growth can really be beneficial to understand the atomic layer growth and film formation in each individual ALD cycle.

1993 ◽  
Vol 324 ◽  
Author(s):  
N. Dietz ◽  
D.J. Stephens ◽  
G. Lucovsky ◽  
K.J. Bachmann

AbstractBrewster Angle Reflectance Differential Spectroscopy (BARDS) has been proposed as an optical method for real-time characterization of the growth of thin films. BARDS is based on changes in the reflectivity, Rp, of parallel (p)-polarized light incident at, or near, the Brewster angle of the substrate material. Changes in R are sufficiently large to monitor layer growth, and to determine the thickness and the optical constants of the deposited film. In this paper we extend the method to multilayer film deposition. The derivative properties of R are correlated with differences in the optical constants of the two materials, and with the sharpness of their interface. We present spectra for SiO2/Si3N4/SiO2/Si, demonstrating some of these aspects of this new and effective approach to in-situ monitoring.


APL Materials ◽  
2016 ◽  
Vol 4 (8) ◽  
pp. 086111 ◽  
Author(s):  
J. P. Podkaminer ◽  
J. J. Patzner ◽  
B. A. Davidson ◽  
C. B. Eom

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 978
Author(s):  
Ming-Jie Zhao ◽  
Zhi-Xuan Zhang ◽  
Chia-Hsun Hsu ◽  
Xiao-Ying Zhang ◽  
Wan-Yu Wu ◽  
...  

Indium oxide (In2O3) film has excellent optical and electrical properties, which makes it useful for a multitude of applications. The preparation of In2O3 film via atomic layer deposition (ALD) method remains an issue as most of the available In-precursors are inactive and thermally unstable. In this work, In2O3 film was prepared by ALD using a remote O2 plasma as oxidant, which provides highly reactive oxygen radicals, and hence significantly enhancing the film growth. The substrate temperature that determines the adsorption state on the substrate and reaction energy of the precursor was investigated. At low substrate temperature (100–150 °C), the ratio of chemically adsorbed precursors is low, leading to a low growth rate and amorphous structure of the films. An amorphous-to-crystalline transition was observed at 150–200 °C. An ALD window with self-limiting reaction and a reasonable film growth rate was observed in the intermediate temperature range of 225–275 °C. At high substrate temperature (300–350 °C), the film growth rate further increases due to the decomposition of the precursors. The resulting film exhibits a rough surface which consists of coarse grains and obvious grain boundaries. The growth mode and properties of the In2O3 films prepared by plasma-enhanced ALD can be efficiently tuned by varying the substrate temperature.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Pawel Sikorski

AbstractBiocementation is commonly based on microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP), where biomineralization of $$\text {CaCO}_{3}$$ CaCO 3 in a granular medium is used to produce a sustainable, consolidated porous material. The successful implementation of biocementation in large-scale applications requires detailed knowledge about the micro-scale processes of $$\text {CaCO}_{3}$$ CaCO 3 precipitation and grain consolidation. For this purpose, we present a microscopy sample cell that enables real time and in situ observations of the precipitation of $$\text {CaCO}_{3}$$ CaCO 3 in the presence of sand grains and calcite seeds. In this study, the sample cell is used in combination with confocal laser scanning microscopy (CLSM) which allows the monitoring in situ of local pH during the reaction. The sample cell can be disassembled at the end of the experiment, so that the precipitated crystals can be characterized with Raman microspectroscopy and scanning electron microscopy (SEM) without disturbing the sample. The combination of the real time and in situ monitoring of the precipitation process with the possibility to characterize the precipitated crystals without further sample processing, offers a powerful tool for knowledge-based improvements of biocementation.


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