rus
Issue #7/2024
D. V. Gorelov, N. M. Somov, I. V. Potapenko, D. V. Novikov, V. V. Amelichev
Study of the Absorption Spectrum of Surface-Modified Silicon Within the Wavelength Range from 2.5 to 25 μm
Study of the Absorption Spectrum of Surface-Modified Silicon Within the Wavelength Range from 2.5 to 25 μm
DOI: 10.22184/1993-7296.FRos.2024.18.7.536.538
Study of the Absorption Spectrum of Surface-Modified Silicon within the Wavelength Range from 2.5 to 25 μm
D. V. Gorelov 1, N. M. Somov 1, I. V. Potapenko 1, D. V. Novikov 1, 2, V. V. Amelichev 1
Federal State Budgetary Research Institution Scientific-Manufacturing Complex “Technological Center”, Zelenograd, Moscow, Russia
National Research University of Electronic Technology “MIET”, Zelenograd, Moscow, Russia
The optimization results of the generation technology for the modified absorption silicon surfaces are provided that allows to improve the spectral characteristics of devices obtained on its basis: radiation cooling devices, IR sources and sensors.
Key words: silicon surface modification, plasma-chemical etching, optical absorption, IR range
Article received: 18.09.2024
Article accepted: 04.10.2024
The surface-modified silicon is a micro-point structure. One of its generation methods is deep anisotropic etching [1]. Due to this surface morphology, a continuous change in the refraction index is achieved that efficiently increases the absorption of optical radiation [2]. The obtained surface-modified silicon with a micro-point height of h ≈ 10 μm demonstrated a high surface absorption capacity of over 90% within the wavelength range from 2.5 to 23 μm. The optical properties of microstructurized silicon allow it to be used in photovoltaics, in the development of biosensors, light-emitting devices, gas-sensitive detectors and antibacterial coatings [3–5].
To obtain the surface-modified silicon, the silicon plasma-chemical etching (PCE) process in SF6 / C4F8 plasma (Bosch process) through the photoresist mask and SiO2 with the dimensions of etching area of 10 × 10 mm and 15 × 15 mm was used. The etching process was performed using a Sentech SI 500 unit. The parameters of the silicon etching mode according to the Bosch process are given in the table.
The standard substrates of single-crystalline silicon of the KEF‑4.5 (100) brand with one-side polishing were used as the plates. The obtained silicon surface morphology studied using the scanning electron microscopy (SEM), is shown in Fig. 1.
The silicon PCE according to the Bosch process is cyclical and consists of three stages: the stage of polymer ion-beam etching (cleaning) at the bottom of the structure, the stage of the main etching, and the stage of polymer deposition. Thus, to generate a surface-modified silicon layer, it is necessary to strike a balance between the stages of etching and polymer deposition, so that the polymer deposition does not interfere with etching, while forming a lot of silicon micro-points. The etching/deposition ratio was regulated by the stage duration. The height of the silicon micro-points was regulated by the number of etching/deposition cycles.
The optical properties of surface-modified silicon are studied using the IR spectroscopy with a Fourier transformation on an FSM 2201/2202 spectrometer within the wavelength range from 2.5 to 25 μm. A comparison of the absorption spectra before and after silicon PCE according to the Bosch process is shown in Fig. 2.
The obtained dependences demonstrate that the absorption of surface-modified silicon is more than 90% within the range from 2.5 to 23 μm. The completed silicon etching mode can be used to obtain the surface-modified silicon with the increased absorption capacity in a wider spectral range [6]. The generation of absorption surfaces will improve spectral characteristics of the radiation cooling devices, IR sources and sensors.
Acknowledgement
This article was prepared with the financial support of the Ministry of Education and Science of the Russian Federation as a part of the implementation of research project FNRM‑2022-0009.
AUTHORS
D. V. Gorelov. ORCID: 0000-0002-0887-9406
N. M. Somov. ORCID: 0009-0009-9093-3018
I. V. Potapenko. ORCID: 0009-0007-4500-1022
D. V. Novikov. ORCID: 0000-0002-9518-1208
V. V. Amelichev. ORCID: 0000-0002-4204-2626
D. V. Gorelov 1, N. M. Somov 1, I. V. Potapenko 1, D. V. Novikov 1, 2, V. V. Amelichev 1
Federal State Budgetary Research Institution Scientific-Manufacturing Complex “Technological Center”, Zelenograd, Moscow, Russia
National Research University of Electronic Technology “MIET”, Zelenograd, Moscow, Russia
The optimization results of the generation technology for the modified absorption silicon surfaces are provided that allows to improve the spectral characteristics of devices obtained on its basis: radiation cooling devices, IR sources and sensors.
Key words: silicon surface modification, plasma-chemical etching, optical absorption, IR range
Article received: 18.09.2024
Article accepted: 04.10.2024
The surface-modified silicon is a micro-point structure. One of its generation methods is deep anisotropic etching [1]. Due to this surface morphology, a continuous change in the refraction index is achieved that efficiently increases the absorption of optical radiation [2]. The obtained surface-modified silicon with a micro-point height of h ≈ 10 μm demonstrated a high surface absorption capacity of over 90% within the wavelength range from 2.5 to 23 μm. The optical properties of microstructurized silicon allow it to be used in photovoltaics, in the development of biosensors, light-emitting devices, gas-sensitive detectors and antibacterial coatings [3–5].
To obtain the surface-modified silicon, the silicon plasma-chemical etching (PCE) process in SF6 / C4F8 plasma (Bosch process) through the photoresist mask and SiO2 with the dimensions of etching area of 10 × 10 mm and 15 × 15 mm was used. The etching process was performed using a Sentech SI 500 unit. The parameters of the silicon etching mode according to the Bosch process are given in the table.
The standard substrates of single-crystalline silicon of the KEF‑4.5 (100) brand with one-side polishing were used as the plates. The obtained silicon surface morphology studied using the scanning electron microscopy (SEM), is shown in Fig. 1.
The silicon PCE according to the Bosch process is cyclical and consists of three stages: the stage of polymer ion-beam etching (cleaning) at the bottom of the structure, the stage of the main etching, and the stage of polymer deposition. Thus, to generate a surface-modified silicon layer, it is necessary to strike a balance between the stages of etching and polymer deposition, so that the polymer deposition does not interfere with etching, while forming a lot of silicon micro-points. The etching/deposition ratio was regulated by the stage duration. The height of the silicon micro-points was regulated by the number of etching/deposition cycles.
The optical properties of surface-modified silicon are studied using the IR spectroscopy with a Fourier transformation on an FSM 2201/2202 spectrometer within the wavelength range from 2.5 to 25 μm. A comparison of the absorption spectra before and after silicon PCE according to the Bosch process is shown in Fig. 2.
The obtained dependences demonstrate that the absorption of surface-modified silicon is more than 90% within the range from 2.5 to 23 μm. The completed silicon etching mode can be used to obtain the surface-modified silicon with the increased absorption capacity in a wider spectral range [6]. The generation of absorption surfaces will improve spectral characteristics of the radiation cooling devices, IR sources and sensors.
Acknowledgement
This article was prepared with the financial support of the Ministry of Education and Science of the Russian Federation as a part of the implementation of research project FNRM‑2022-0009.
AUTHORS
D. V. Gorelov. ORCID: 0000-0002-0887-9406
N. M. Somov. ORCID: 0009-0009-9093-3018
I. V. Potapenko. ORCID: 0009-0007-4500-1022
D. V. Novikov. ORCID: 0000-0002-9518-1208
V. V. Amelichev. ORCID: 0000-0002-4204-2626
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