PREPARATION OF ERBIUM SULFIDE BY CVD METHOD

ABSTRACT

The paper considers the sulfidization of erbium, consisting of two stages: the method of preliminary deposition of zinc on substrates by physical vacuum deposition (PWD) on a magnetron installation, followed by vacuum chemical deposition on a chemical vacuum deposition(CVD) laboratory installation in the framework of obtaining technology for the production of erbium sulfide.

АННОТАЦИЯ

В работе рассматривается сульфидизация эрбия, состоящая из двух этапов: метод предварительного нанесения цинка на подложки методом физического вакуумного осаждения(PWD) на магнетронной установке с последующим вакуумным химическим осаждением на лабораторной установке химического вакуумного осаждения (CVD) в рамках получения технологии производства сульфида эрбия.

Keywords: Er; Er; CVD; PWD; KBr; laboratory installation; vacuum installation; erbium sulfidization; erbium precipitation.

Ключевые слова: ErS; Er; CVD; PWD; KBr; лабораторная установка; вакуумная установка; сульфидизация эрбия; осаждение эрбия.

1. Introduction

The process analog of applying erbium to substrates is described in detail in other works of the author.  [1,2] KBr and quartz plates were used in a system with nanocrystalline erbium films. [3]

After spraying erbium by the PWD method, the plates were transferred to another laboratory installation for CVD synthesis, which is also described in another work [3] In the CVD installation, the plate interacted in a vacuum reactor[2] heated by a furnace with an argon cylinder, which was regulated after a series of experiments [3] by the system, in the near region to the reactor there was an additional furnace responsible for heating sulfur.

2. Research methodology

The initial production of erbium was carried out using the PWD technique on a magnetron installation [1] in Fig. 1.

Figure 1. Magnetron installation [1]

For our process, a vacuum of 10-3 mm/Hg was used, which can be created by a pump system: the forevacuum is paired with a diffusion of a given performance.[1]

In the magnetron chamber , the process looked according to the fig. 2.

Figure 2. The process of applying erbium to KBr and quartz substrates.

The general view of the laboratory installation is indicated in the form of a 3D model in Fig. 3.

Figure 3. 3D Model of the CVD laboratory installation system [3]

Figure 4. Tecnological scheme of production. 1 – Pre-vacuum pump, 2 – gas mixer, 3 – pressure gauge, 4 – furnace, 5 – quartz reactor, 6 – SOM, 7 – boats with evaporable material, 8 – balloon reduction gearboxes, 9 – PPG [3]

Erbium [4] was placed throughout the reactor area in order to quickly select the optimal sulfidization temperature. The temperature of zone 1 (reactor) and zone 2 (furnace with a sulfur boat) varied according to the table. Photos of the obtained samples were selected from each batch according to the most suitable characteristics of the desired compound.

The data are summarized in table 1:

Table 1.

Experiments on erbium sulfidization

To calculate the location of samples[5] on the surface inside the quartz reactor, the Fusion 360 Autodesk program (License version for students) was used, in which the distribution of the components of the experiment was performed, images from 3D models are shown in Fig 5-9.

Figure 5. 3D model of sample distribution over the quartz reactor of experiment № 1

Figure 6. 3D model of sample distribution over the quartz reactor of experiment № 2

Figure 7. 3D model of sample distribution over the quartz reactor of experiment № 3

Figure 8. 3D model of sample distribution over the quartz reactor of experiment №. 4

Figure 9. 3D model of sample distribution over the quartz reactor of experiment № 5

The distances from the beginning of the quartz tube[6] to the samples were selected experimentally, schematically the data were transferred to Fig. 10-14

Figure 10. Schematic representation of the location of the samples[7,8] and the boat S inside the reactor, experiment № 1

Figure 11. Schematic representation of the location of the samples and the boat S inside the reactor, experiment № 2

Figure 12. Schematic representation of the arrangement of samples and boat S inside the reactor, experiment № 3

Figure 13. Schematic representation of the location of the samples and the boat S inside the reactor, experiment № 4

Figure 14. Schematic representation of the location of the samples and the boat S inside the reactor, experiment № 5

Figure 15. Results of additional experiment № 6 for visual analysis of all obtained samples of erbium compounds of Experiment №. 6, the conditions of internal chemical processes are similar to experiment № 5 from Table 4. 1 – 5 cm from the beginning of the reactor[9], sample 2 – 15 cm from the beginning of the reactor, sample 3 – 20 cm from the beginning of the reactor, sample 4 – 27 cm from the beginning of the reactor. The remaining sample data[10] are listed in Table 1

3. Results and discussion

Microscopy of Er samples was performed under the following conditions.

Optical spectroscopy was performed on a Fourier spectrometer - a two–beam Michelson interferometer.

The X-ray phase analysis was performed on an X-ray analytical microprobe-the RAM-30µ microscope, which is designed for the study of objects by methods of local elemental microanalysis with the possibility of micro-mapping, transmission radiography and optical microscopy.

А)

B)

C)

D)

E)

Figure 16. Microscopy[11] of samples №.1-5 corresponding to A-D

А)

B)

C)

D)

E)

Figure 17. Microscopy of samples №.1-5 corresponding to A-D (elemental composition)

As we can see from Fig. 16 and Fig. 17, a large content of erbium Er and sulfur S with oxygen O prevails on the substrate surface, which means that the etching of samples had to be carried out initially longer. Erbium sulfide Er was obtained.

4. Conclusions

The films have acceptable adhesion, are sufficiently dense, stoichiometric, have a wurtzite structure, and there is also a tendency for monoclinic and hexagonal structures to grow on the substrate surface. It can be assumed that the growth of the film takes place in the Stransky-Krastanov mode, when the first layer completely covers the surface of the substrate, and three-dimensional islands of the wurtzite film grow on it. Further, the lattice parameter cannot remain unchanged when filling the next layer. Its change leads to a strong increase in the energy of the adsorbent - intermediate layer interface, which ensures the fulfillment of the island mode criterion.

Referenses:

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2. Dudaeva L.G., Semencha A.V. OBTAINING NANOCRYSTALLINE ZINC FILMS BY MAGNETRON SPUTTERING// Proceedings of the XXXV International Multidisciplinary Conference «Recent Scientific Investigation». Primedia E-launch LLC. Shawnee, USA. 2022. DOI:10.32743/UsaConf.2022.8.35.344301;
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