Self-assembled nano-dots structures on Si(111) surfaces by oblique angle sputter-deposition

Gupta, Divya; Kumari, Rimpi; Umapathy, G.R.; Singhal, Rahul; Ojha, Sunil; Sahoo, Pratap K.; Aggarwal, Sanjeev

doi:10.1088/1361-6528/ab273a

Cited by 10 publications

(18 citation statements)

References 44 publications

(102 reference statements)

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“…After amorphization at different oblique incidences of 50°, 40° and 30°, the presence of damage peak in RBS/C spectra at channel no. 1059 along the ⟨111⟩ axis reveal the formation of amorphous layer due to argon beam induced disordering in the silicon lattice 31 . The channeled backscattering yield corresponding to this damage peak decreases with decrease in oblique incidence (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…PARAS facility at Inter University Accelerator Center, New Delhi has been employed in random and channeling geometry for RBS measurements. Channeling experiments were carried out with ion beam parallel to (111) axis [30][31][32] and corresponding image and angle scan have been collected by NEC's RC43 Software. The damage profiles were simulated from the RBS/C spectra using the code DICADA, which is based on the continuous model of dechanneling 14 .…”

Section: Methodsmentioning

confidence: 99%

“…For un-irradiated and unannealed Si(111), the backscattering yield of the amorphous peak along the ⟨111⟩ axis is found to be only 5%, which signifies the high crystalline quality of the surface layers 31 .…”

Section: Rbs/c Investigations Of As Amorphized and Recrystallized Si(mentioning

confidence: 96%

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Nano-scale depth-varying recrystallization of oblique Ar+ sputtered Si(111) layers

Gupta

Umapathy

Singhal

et al. 2020

Sci Rep

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Silicon, the workhorse of semiconductor industry, is being exploited for various functional applications in numerous fields of nanotechnology. In this paper, we report the fabrication of depth controllable amorphous silicon (a-Si) layers under 80 keV Ar + ion sputtering at off-normal ion incidences of 30°, 40° and 50° and crystallization of these amorphous Si(111) layers under thermal annealing. We find that the irradiated samples were not fully amorphized even for the lowest oblique incidence of 30°. Sputtering at off-normal incidences induces depth controllable surface amorphization in Si(111). Annealing at temperature of 1,073 K is characterized by formation of depth-varying buried amorphous layer due to defect recrystallization and damage recovery. Some remnant tensile stress has been observed for recrystallized samples even for lowest oblique incidence. the correlation of amorphization and stress due to sputtering induced by oblique incidence has been discussed systematically. the possible mechanism of recrystallization is discussed in terms of vacancies produced in sputtering dominated regime and their migration during annealing treatment. our results reveal that with appropriate selection of oblique ion beam sputtering parameters, depth controllable surface amorphization and recrystallization may be fine-tuned to achieve co-existing amorphous and crystalline phases, playing a crucial role in fabrication of substrates for ic industry. Silicon, the workhorse of semiconductor industry, is being exploited for the various applications in numerous fields of nanotechnology like development of FETs and infrared detectors 1-3. The combined amorphous and crystalline phases of silicon play a crucial role in the fabrication of substrates for IC industry and hence, deciding circuit performance and reliability 4-6. The process of ion implantation has become a versatile tool for producing doped regions in FETs source, channel and drain in semiconductors 1,4-8. In this regard, low energy ion irradiation is widely employed in IC industry for producing bipolar transistors in semiconductors, especially in silicon substrates. This technique offers advantage of implanting controllable quantity of incident ions into the shallow surface layers of substrate with good accuracy 5-8. In addition to these beneficial features, this non-equilibrium method disorders the equilibrium crystalline structure of the single crystal material by inducing amorphization as well as damage in the lattice 5-7,9,10. The extent and nature of these ion beam induced imperfections in the lattice limits the performance and reliability of semiconductor devices and circuits 1,6,11. This, in turn, necessitates the recovery of crystalline order of the lattice 5,9,10,12,13. It is well known that recovery from disordered surface layers is eventually a diffusive process. Hence, the well known viable tool for restoring ordered crystalline structure, recovery of ion beam induced imperfections & defects and activation of dopants is thermal annealing 4,9,10,12. Ion i...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Nano-scale depth-varying recrystallization of oblique Ar+ sputtered Si(111) layers

Gupta

Umapathy

Singhal

et al. 2020

Sci Rep

Self Cite

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“…Oblique angle sputter erosion (OASE) is a versatile and cost-effective tool for patterning and structuring solid surfaces at the nanoscale level [1][2][3]. This is a scalable method that fabricates a myriad of patterns in a single technological step and is applicable to most solid materials, ranging from metals to semiconductors, and from organic to inorganic materials [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Ripple pattern formation on silicon carbide surfaces by low-energy ion-beam erosion

Gupta

Umapathy

Singhal

et al. 2023

J. Phys.: Conf. Ser.

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A versatile experimental facility air insulated high current medium energy 200 kV Ion Accelerator, with the terminal voltage in the range of 30-200 kV has been running successfully at Ion Beam Centre, KUK for carry out multifarious experiments in material science and surface physics. This system offers single charge state, switching magnet with five exit ports and large area irradiation/implantation using hollow cathode ion source. Ion beam induced structures on the surfaces of semiconductors have potential applications in photonics, magnetic devices, photovoltaics, and surface-wetting tailoring etc. In this regard, silicon carbide (SiC) is a fascinating wide-band gap semiconductor for high-temperature, high-power and high-frequency applications. In this work, fabrication of ripple patterns is carried out on the SiC surfaces using 80 keV Ar+ ion beam for different fluences at oblique incidence of 500. AFM study demonstrates that ripple wavelength and amplitude, ordering and homogeneity of these patterns vary linearly with argon ion fluence. The formation of such surface structures is attributed to the preferential sputtering of silicon in comparison to carbon. The evolution of high degrees of order is explained with the help of existing formalisms of coupling between surface topography and preferential sputtering.

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“…Under ion irradiation, the balance between sputtering-induced surface roughening and diffusion-induced smoothing determines the behaviour of solid surfaces. Irradiating materials using keV ions (also known as low energy ions) produce regular surface structures like ripples[2-4], and dots [5]. Most of these ions are stopped in their tracks by nuclei, causing the energy to be dispersed over a large area.…”

Section: Introductionmentioning

confidence: 99%

Fractal characterizations of MeV ion fractured CaF2 thin films

Pandey

Yadav

Kumar

et al. 2022

Preprint

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We present the morphological evolution and fractal characterization of CaF2 thin film surfaces modified by bombardment with 100 MeV Au+8 ions at various fluences. Atomic force microscopy (AFM) combined with line profile and two-dimensional power spectral density (2D-PSD) analysis was utilized to investigate the evolution of surface morphology as a function of fluence. The AFM images were utilized to investigate the relationship between fractal dimension, roughness exponent, lateral correlation length, and ion fluence. The surface erosion owing to sputtering was depicted using Rutherford backscattering spectrometry (RBS). The structural characteristics’ dependency on fluence was explored with the help of glancing angle X-ray diffraction (GAXRD) measurements on virgin and irradiated samples. Tensile stress calculated using peak shift in the glancing angle X-ray diffractogram showed an increase in tensile stress with fluence that caused the surface to crack after the fracture strength of the surface was crossed. 2D-PSD analysis signified the role of sputtering over surface diffusion for the observed surface modifications. Fractal dimensions first increased and then decreased with ion fluence. Lateral correlation length decreased while roughness exponent increased with fluence after the threshold value.

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Self-assembled nano-dots structures on Si(111) surfaces by oblique angle sputter-deposition

Cited by 10 publications

References 44 publications

Nano-scale depth-varying recrystallization of oblique Ar+ sputtered Si(111) layers

Nano-scale depth-varying recrystallization of oblique Ar+ sputtered Si(111) layers

Ripple pattern formation on silicon carbide surfaces by low-energy ion-beam erosion

Fractal characterizations of MeV ion fractured CaF2 thin films

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