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1
Content available remote

Two-Dimensional Simulations of H¯ Ions Extraction

100%
Turek M.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
254-258
EN
The 2D particle-in-cell method based model of a negative ion source is presented. The spatial distributions of electrostatic potential and plasma component densities are presented. Changes of negative ion distribution and potential as well as the extracted H¯ current with the plasma grid bias voltage are investigated. The presence of the potential well near the plasma grid surface that traps the negative ions is shown. Increase of the H¯ ions density inside the chamber with the negative bias voltage is demonstrated. Influence of the H¯ ion flux outgoing from the plasma grid on the extracted current was checked: increase by factor 2 is observed when the flux rises 4 times. Current-voltage characteristics of the ion source are presented, saturation of the curve is observed above 50 kV.
2
Content available remote

Ionisation Efficiency in Conical Hot Cavities

100%
Turek M.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
259-263
EN
Surface ionisation in a new type of hot cavity characterised by the shape of a truncated cone is considered in the paper. Influence of the hot cavity shape and its temperature on the ionisation efficiency of stable and long-lived nuclides is under investigation and the supremacy of elongated conical cavities is proven. The role of the extraction opening size is studied and its optimal diameter ( ≈ 1 mm) is found for the considered cavity shapes. It is shown that the extraction voltages of 1-2 kV are large enough to obtain high efficiencies and saturation of the current-voltage curves is observed above these values. Changes of ionisation effciency with the ioniser temperature are investigated - increase of ion yield with T is observed. It was proven that cold spots inside the ioniser cavity (near the extraction opening - in the considered case) can degrade ion source performance by several tens percent.
3
Content available remote

Effects of Electron Impact on Ionization of Short-Lived Isotopes in a Hot Cavity

100%
Turek M.
|
|
vol. 125
|
issue 6
1384-1388
EN
A Monte Carlo method based numerical model of hot cavity surface ion source that takes into account radioactive decay and the delay due to the sticking of particles to ionizer surface is considered. The influence of electron impact ionization by thermionic electrons accelerated by the extraction field is investigated. It is shown that the contribution from that process rises with decreasing half-life period and cannot be neglected, especially for substances of small surface ionization coefficient. The changes of relative yields from electron impact and surface processes with the length of the average sticking time are also studied.
4
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Modeling of Ionization in a Spherical Surface Ionizer

100%
Turek M.
Acta Physica Polonica A
|
2011
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vol. 120
|
issue 1
188-191
EN
A Monte Carlo method-based model of a hot cavity surface ion source with a spherically shaped ionizer is presented. A numerical code enables studies of ion source efficiency as a function of an extraction voltage, geometry of the ionizer and its temperature, the size of extraction aperture and many other factors. The calculation results for a variety of mentioned parameters are presented. A novel configuration of surface ion source is proposed and discussed - the efficiency of the source with an almost spherically shaped ionizer could be much higher than that of currently used constructions of ion sources.
5
Content available remote

Surface Ionization of Radioactive Nuclides - Numerical Simulations

100%
Turek M.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 5
847-850
EN
The Monte Carlo method based model of the ionization in the hot cavity taking into account radioactive decay of nuclides is presented. The code upgraded compared to the previous version enables calculation of the ion source ionization efficiency not only for different geometries and temperatures of the ionizer, extraction voltages etc. but also gives opportunity of setting different values of the nuclide half-life and its sticking time, which may be considered as the main factor determining the time that a particle spends in the ion source. The results of calculations are presented together with the discussion of the radioactive decay on the ion source performance.
6
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Calculations of Ion Beam Emittance for Hot Cavity Ion Source

100%
Turek M.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
931-934
EN
Emittance of short-lived nuclide beams produced in hot cavity ion sources is calculated. Influence of half-life period as well as the average sticking time on beam emittance is under investigation. Two different shapes of ionizer cavity are considered: almost fully spherical and hemispherical ones. Changes of beam emittance due to the extraction channel geometry (its diameter and length) are studied. A new concept of scaled efficiency (ion source brightness analogon) is introduced in order to compare the two-ion source configurations. Phase space portraits of the extracted beams are presented.
7
Content available remote

Ionization of Short-Lived Isotopes in Spherical Hot Cavities

100%
Turek M.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
935-938
EN
The numerical model of ionization of short-lived nuclides in spherical hot cavities is presented. Two different cavity configurations are considered: one of them (the hemispherical one) resembles that known from already existing ion sources while the other (closer to the full sphere) could be more efficient for short-lived isotopes. Changes of ionization efficiency with the half-life period as well as with the particle average sticking time are presented and discussed. Influence of the extraction opening radius on ionization efficiency is also under investigation.
8
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Application of Ion Implantation for Intermediate Energy Levels Formation in the Silicon-Based Structures Dedicated for Photovoltaic Purposes

51%
Billewicz P., Węgierek P., Grudniewski T., Turek M.
Acta Physica Polonica A
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2017
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vol. 132
|
issue 2
274-277
EN
The main aim of the research was to verify if it is possible to create the intermediate energy levels in silicon by means of ion implantation as well as to confirm whether the intermediate band could arise. The tests covered recording of conductance and capacitance of antimony-doped silicon, implanted with Ne⁺ ions. As a result, it was possible to identify a single deep level in the sample and determine its location in the band gap by estimating the value of activation energy.
9
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Tailoring the Internal Evaporator for Effective Ion Beam Production - Volatile vs. Non-Volatile Substances

51%
Turek M., Droździel A., Pyszniak K., Prucnal S.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
939-942
EN
Two different designs of the internal evaporator in an arc discharge ion source are presented, suitable either for volatile, or high-melting point substances. A matter of the evaporator size and placement in order to obtain its appropriate temperature and, therefore, a stable and intense ion beam, is considered. Basic ion source characteristics, i.e. the dependences of ion current and discharge voltage on the discharge and filament currents as well as on the external magnetic field flux density are shown and discussed in order to find optimal working conditions. The results of measurements for both volatile (P, Zn, Se, S) and non-volatile (Pd) are presented, showing the applicability of the design for ion implantation purposes.
10
Content available remote

Production of Mo^{+} Beams Using an Arc Discharge Ion Source

45%
Turek M., Droździel A., Pyszniak K., Prucnal S., Mączka D.
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vol. 125
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issue 6
1388-1391
EN
A new method of Mo^{+} ion beam production is presented in the paper. The method bases on the chemical sputtering/etching of the molybdenum parts (e.g. anode) of the arc discharge ion source by the chloride containing plasma. A mixture of CCl_4 (or CHCl_3) vapor and air was used as the feeding substance. The separated Mo^{+} beam current of approximately 18 μA was achieved. The measurements of the ion current dependences on the discharge and filament currents as well as on the magnetic field flux density from the electromagnet surrounding the discharge chamber were performed in order to find the optimal working parameters of the ion source.
11
Content available remote

Production of Doubly Charged Ions Using a Hollow Cathode Ion Source with an Evaporator

45%
Turek M., Droździel A., Pyszniak K., Mączka D., Słowiński B.
Acta Physica Polonica A
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2013
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vol. 123
|
issue 5
843-846
EN
The paper describes the production of doubly charged ions from solids and gases using a hollow cathode ion source with an internal evaporator heated by a spiral cathode filament and arc discharge. The obtained currents were 15 μA for Bi^{2+}, 10 μA for As^{2+} and Al^{2+}, 8 μA for Kr^{2+} and Xe^{2+}, 5 μA for In^{2+} and Ge^{2+}, enabling moderate dose implantations ( ≈ 10^{15} cm^{-3}) with doubly charged ions. Characteristics of the ion source are presented and discussed in order to choose the optimal working parameters. A brief presentation of numerical model of doubly and singly charged ions in the ion source is given. The calculated results (dependences of ion current on the anode voltage) are in good agreement with the experimental data.
12
Content available remote

Plasma Ion Source with an Internal Evaporator

45%
Turek M., Droździel A., Pyszniak K., Prucnal S., Mączka D.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
184-187
EN
A new construction of a hollow cathode ion source equipped with an internal evaporator heated by a spiral cathode filament and arc discharge is presented. The source is especially suitable for production of ions from solids. The proximity of arc discharge region and extraction opening enables production of intense ion beams even for very low discharge current (I_{a} = 1.2 A). The currents of 50 μA (Al^{+}) and 70 μA (Bi^{+}) were obtained using the extraction voltage of 25 kV. The source is able to work for several tens of hours without maintenance breaks, giving possibility of high dose implantations. The paper presents the detailed description of the ion source as well as its experimental characteristics like dependences of extracted currents and anode voltage on anode and cathode currents.
13
Content available remote

Thermal Desorption of Krypton Implanted into Silicon

39%
Turek M., Droździel A., Wójtowicz A., Filiks J., Pyszniak K., Mączka D., Yuschkevich Y.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
249-253
EN
The thermal desorption spectrometry studies of krypton implanted Si samples are presented. Implantations (with the fluence 2×10¹⁶ cm¯²) were done with the energies 100, 150, and 200 keV. Additionally, a 200 keV and 100 keV Kr⁺G double implantation was performed. A sudden Kr release was observed in the ≈1100-1400 K range, most probably coming from the gas bubbles in cavities. The desorption activation energy varies from 2.5 eV (100 keV) to 0.8 (200 keV). The peak splitting suggests existence of two kinds of cavities trapping the implanted noble gas. Two Kr releases are observed for the 200 and 100 keV double-implanted samples. The peak shift of the release corresponding to 100 keV implantation could be a result of both introduced disorder and higher effective Kr concentration. The desorption activation energy is risen to ≈3.2 eV for both releases.
14
Content available remote

Depth Profile Analysis of Phosphorus Implanted SiC Structures

39%
Konarski P., Król K., Miśnik M., Sochacki M., Szmidt J., Turek M., Żuk J.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
864-866
EN
Secondary ion mass spectrometry depth profile analyses were performed on two sets of 4H-SiC(0001) substrate samples implanted with phosphorus. Both sets were processed under the same conditions. We implanted the samples with 100 keV (10¹¹-10¹⁴ cm¯²) phosphorus ions through the thin chemical vapor deposition deposited silicon dioxide stopping mask in order to obtain an ultra-shallow implantation profile. After phosphorus implantation, secondary ion mass spectrometry depth profile analysis was performed on the first set of samples and the second set was subjected to thermal oxidation procedure at 1200°C in order to create a dielectric layer. The aim of the oxidation process was formation of the silicon dioxide layer enriched with phosphorus: the element, which is considered to be suitable for trap density reduction. Ion implantation parameters as well as oxidation and chemical etching procedures were examined for the proper incorporation of phosphorus into the subsurface structure of the silicon oxide. Secondary ion mass spectrometry depth profile analysis was performed with Physical Electronics 06-350E sputter ion gun and QMA-410 Balzers quadrupole mass analyser. The analytical parameters such as: 1.7 keV Ar⁺ ion beam digitally scanned over 3×3 mm² area and ion erosion rate of 1.4 nm/min and sampling rate of 0.3 nm, were suitable for samples oxidized after ion implantation.
15
Content available remote

Thermal Desorption of Helium from Defected Silicon

33%
Turek M., Droździel A., Pyszniak K., Wójtowicz A., Mączka D., Yuschkevich Y., Vaganov Y., Żuk J.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
849-852
EN
The thermal desorption spectroscopy measurements of He implanted silicon samples are reported. The He implantation energy was 90 keV (at 45° tilt) while the fluence was 10¹⁶ cm¯². Additionally, the influence of Si pre-implantation (fluences in the range 10¹⁴-10¹⁶ cm¯², E=260 keV) was under investigation. The He releases from both interstitials/vacancies (β peak) and cavities (α peak or rather band consisting probably of at least two peaks) were observed. The α peak disappears for the pre-implantation fluences larger than 10¹⁵ cm¯², while β peak becomes broader and shifts toward higher temperatures. The thermal desorption spectra were collected using heating ramp rates in the range 0.3-0.7 K/s. Desorption activation energy of the β peak for different pre-implantation fluences was found using the Redhead analysis of the β peak shift. It varies from 0.97 eV for the sample that was not pre-implanted up to 1.3 eV for the sample pre-implanted with the fluence 10¹⁶ cm¯².
16
Content available remote

III-V Quantum Dots in Dielectrics Made by Ion Implantation and Flash Lamp Annealing

33%
Prucnal S., Turek M., Gao K., Zhou S., Pyszniak K., Droździel A., Żuk J., Skorupa W.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 5
935-938
EN
Different semiconductor nanocrystals synthesized in dielectrics on silicon are very interesting for applications in non-volatile memories and photovoltaics. In this paper we present an overview of microstructural and opto-electronic properties of different III-V quantum dots embedded in SiO_2 and Si_3N_4 made by sequential ion implantation and millisecond range flash lamp annealing. It is shown that within 20 ms post-implantation annealing high quality crystalline III-V quantum dots can be formed in different matrices. Formation of crystalline III-V quantum dots was confirmed by cross-section transmission electron microscopy, photoluminescence and μ-Raman spectroscopy. Flash lamp annealing is essentially a single-flash-single-wafer technique whose main attributes are the ease and control of processing over large wafer batches.
17
Content available remote

Production of Molybdenum and Tantalum Ion Beams using CCl₂F₂

33%
Turek M., Droździel A., Pyszniak K., Filiks J., Prucnal S., Mączka D., Vaganov Y., Węgierek P.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
283-287
EN
A new method of refractory metal (like Mo and Ta) ion beam production using the arc discharge ion source and CCl₂F₂ (dichlorodifluoromethane) used as a feeding gas supported into the discharge chamber is presented. It is based on etching of the refractory metal parts (e.g. anode or a dedicated tube) Cl and F containing plasma. The results of measurements of the dependences of ion currents on the working parameters like discharge and filament currents as well as on the magnetic field flux density of an external electromagnet coil are shown and discussed. The separated Mo⁺ and Ta⁺ beam currents of approximately 22 μA and 2 μA, respectively, were obtained.
18
Content available remote

Modification of Optical and Electrical Properties of PET Foils by He⁺, Ne⁺ and Ar⁺ Implantation

33%
Droździel A., Turek M., Pyszniak K., Prucnal S., Luchowski R., Grudziński W., Klimek-Turek A., Partyka J.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
264-269
EN
Thin (3 μm) polyethylene terephthalate (PET) foils were irradiated with 135 keV He⁺, Ne⁺ and Ar⁺ ions with the fluences up to 5×10¹⁵ cm¯². Changes of chemical structure of the polymer were studied with the Fourier transform infrared and Raman spectroscopy - breaking of numerous chemical bonds, polymer chain cross-linking as well as formation of sp² hybridised carbon clusters and cluster networks were demonstrated. The increase of the implanted sample absorbance with the implantation fluence in the UV-VIS spectra as well as the decrease of optical band-gap energy (2.75 and 2.0 eV for He and Ne, respectively, at 5×10¹⁵ cm¯²) are observed. Decrease of bulk resistance of heavily treated samples by ≈5 orders of magnitude is determined. Measurements of the sheet resistance confirm that the sample becomes conducting also on the reverse (unimplanted) side of the foil. Both of these effects depend on the impinging ion mass - they are the strongest for Ar. The increase of both ac conductance and dielectric constant is observed in the frequency range up to 2 MHz and these changes rise with the impinging ion mass.
19
Content available remote

Thermal Desorption Studies of Ar^{+} Implanted Silicon

33%
Drozdziel A., Wojtowicz A., Turek M., Pyszniak K., Maczka D., Slowinski B., Yushkevich Y., Zuk J.
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|
vol. 125
|
issue 6
1400-1404
EN
Thermal desorption spectrometry measurements were performed for Ar implanted Si samples. Implantation energy E_{i} varied in the range 85-175 keV. The release of implanted Ar in two steps was observed in the temperature range 930-1300 K: the relatively narrow peak at lower temperature ( ≈ 930 K for implantation fluence 5 × 10^{16} cm^{-2}) is due to the release of Ar from the agglomerations (bubbles) while the broader peak observed for higher temperatures ( ≈ 950 K for implantation fluence 5 × 10^{16} cm^{-2}) comes from Ar atoms diffusing out of the sample. Inverse order of peaks is observed compared to the results for lower energy implantations (< 50 keV). Analyzing the thermal desorption spectra collected for different heating ramp rates enabled estimation of the desorption activation energy (2 eV for E_{i} = 85 keV and 1.7 eV for E_{i} = 115 keV).
20
Content available remote

Influence of Hot Implantation on Residual Radiation Damage in Silicon Carbide

33%
Rawski M., Żuk J., Kulik M., Droździel A., Lin L., Prucnal S., Pyszniak K., Turek M.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
192-195
EN
Remarkable thermomechanical and electrical properties of silicon carbide (SiC) make this material very attractive for high-temperature, high-power, and high-frequency applications. Because of very low values of diffusion coefficient of most impurities in SiC, ion implantation is the best method to selectively introduce dopants over well-defined depths in SiC. Aluminium is commonly used for creating p-type regions in SiC. However, post-implantation radiation damage, which strongly deteriorates required electric properties of the implanted layers, is difficult to anneal even at high temperatures because of remaining residual damage. Therefore implantation at elevated target temperatures (hot implantation) is nowadays an accepted method to decrease the level of the residual radiation damage by avoiding ion beam-induced amorphization. The main objective of this study is to compare the results of the Rutherford backscattering spectroscopy with channeling and micro-Raman spectroscopy investigations of room temperature and 500°C Al^{+} ion implantation-induced damage in 6H-SiC and its removal by high temperature (up to 1600°C) thermal annealing.
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