MOCVD laboratory

Contact info: doc. Ing. Novák Jozef, DrSc.

The MOCVD laboratory (established in July 1993) runs two epitaxial equipments from Aixtron provenience. The older equipment, AIXTRON AIX-200 R&D, is a standard research-oriented apparatus allowing growth of III-V semiconductor epitaxial layers and advanced heterostructures on GaAs, GaP, and InP substrates. Elements of group III are supplied from basic organometallic sources, such as trimethylgallium (TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl), and group V elements are incorporated from hydrides, such as arsine (AsH3) and phosphine (PH3). Doping sources used are diethylzinc (DEZn) for Zn and silane for Si. MOCVD equipment is used for the preparation of epitaxial layers, heterostructures, and low dimensional structures in InxGa1-xP/GaAs, AlGaAs/GaAs, InxGa1-xAs/GaAs, and InxGa1-xAs/InP material systems.

Since December 2014 we operate a new Aixtron CCS flip top MOCVD system with shower head-type of reactor. It allows growth on 3x2 or 1x4-inch wafers. This equipment is dedicated for growth of GaN based epitaxial layers and structures. Recently TMGa, TEGa, TMAl, and TMIn sources are incorporated as group III element sources. NH3 serves as a nitrogen source while the silane is used for Si doping. The sources arrangement allows growth of GaN, InAlN, AlGaN, and InGaN layers and structures. Our goal is to optimise growth processes aiming the preparation of layers and heterostructures with high quality crystallographic structure interface quality on the atomic level for application in advanced transistor and photocathode structures.

Scope:

  • MOVPE growth nitrides, arsenides, and phosphides
  • Growth of doped and undoped nanowires including an analysis of early stages of nanowire growth
  • Preparation of photonic structures based on NSOM lithography patterning

Equipment:

  • MOVPE Aixtron CCS 3x2 shower head reactor for GaN and related compounds
  • MOVPE horizontal equipment Aixtron AIX-200 for growth of arsenides and phosphides

       

                                                contact for more info: Ing. S. Hasenöhrl, Ing. J. Kuzmík, DrSc.

 


Laboratory of PLD

Contact info: Ing. Chromik Štefan, DrSc.

The laboratory enables the preparation of different thin films using pulsed laser deposition method. In this method, the laser beam vaporizes the surface of the target, producing a film with the same composition as the target. Due to high temperature of the evaporated material, low deposition temperature and smaller target area in respect to that of the substrate can be used.

Scope:

  • Deposition of high-quality thin superconducting films at low substrate temperatures
  • Deposition of multilayer structures in the same vacuum cycle with a fine control of the film thickness down to atomic monolayer

 

                             


ALD laboratory

Contact info: Ing. Fröhlich Karol, DrSc.

Thin oxide films (Al2O3, TiO2, and HfO2) are prepared using atomic layer deposition. The films are grown using thermal, ozone, and plasma assisted modes at temperatures between ambient up to 350 °C. The films are used for insulation and passivation of the electronic devices (GaN and GaAs-based high electron mobility devices, HEMTs) and as active layers in memory elements based on resistive switching.

Scope:

  • Deposition of thin oxide films with atomic level precision
  • Growth of thin dielectric films with excellent properties at low temperatures
  • Deposition on 3D substrates
  • Modification of films and interfaces on atomic level

                             


Metal Deposition Laboratory

Contact info: Ing. Fedor Ján, PhD.

The laboratory is equipped with sputtering and evaporating machine ATC Orion 8E made by AJA International, Inc. The deposition system is placed in the clean room facility and it enables to deposit metals, insulators and magnetic materials on the samples with maximum diameter of 75 mm. It is used to work on projects related to microelectronics, nanotechnology, and modern environmental and medical sensors R&D.

Scope:

  • Evaporation of materials by two independent electron guns
  • AC and DC sputtering of metallic, insulating, and magnetic materials (co-sputtering, superlattice)
  • Two in situ fed thermal evaporation sources
  • Sample treatment: RF cleaning, ion beam cleaning, rotation and heating up to 850 °C
  • Deposition of materials in different gas environment: N2 (TiN), O2 (Al2O3)

 

   
                                


Nanostructure Laboratory

Contact info: Ing. Vávra I., CSc.

A FEI Quanta 3D Dual microscope is a scanning microscope that works with an electron beam (SEM) and an ion beam (Focused Ion Beam, FIB), and it can manipulate objects and deposit platinum contacts with a micro-manipulator. The system allows for micro and nano patterning, 3D structure nanostructure formation, and analysis of layered and composite nanostructures.

                                  


Plasma Etching Laboratory

Contact info: RNDr. Haščík Štefan, PhD.

The Oxford Instruments - Plasmalab System100 is a state of the art tool for Inductively-Coupled Plasma Reactive Ion Etch (ICP RIE) processing of selected materials. Our research is primarily focused on etching of the GaN, AlGaN, InAlN, GaAs and InN semiconductors. The ICP RIE provides the etch precision and low damage selective reactive ion etching (SRIE) necessary to create next generation microscale (opto-)electronic devices and MEMS. A simple vacuum Load‑lock system is suitable for 4‑inch wafers as well as pieces which can be mounted on a handle wafer. ICP RIE equipment is operated by the control computer located in the clean room.

Scope:

  • Etching of semiconductor materials and heterostructures based on GaN, AlGaN, InAlN, GaAs, and InN using the chlorine chemistry or its mixtures with fluorinated compounds
  • Etching heterostructure layers (AlGaAs, GaAs, InGaAs, and InP) using SiCl4/Cl2, BCl3/Cl2, and Cl2/Ar
  • Etching SiO2, Si3N4 and SiC by the CF4 and SF6 gases

Equipment:

Oxford Plasmalab 100 Inductively Coupled Plasma (ICP) etching system equipped with

  • 13,6 MHz supply with automatic matching at the substrate electrode
  • 3 kW Inductive Coupled Plasma (ICP 180) Source with electrostatic shielding
  • temperature range substrate electrode: -30 + 80°C
  • automatic 4-inch/100 mm wafer Load‑lock system
  • PC Control with OPT PC2000 RIE Software under Windows 7

              


Clean Room Facility

Contact info: Ing. Kováčová Eva

The clean room facility is used to realize modern electronic devices and sensors. According to the US standard, the dust particle count is kept at 100 particles sized 0.5 µm and larger per cubic feet, which matches the levels in production facilities of producers of electronic circuits. The facility contains two rooms and is equipped with a Karl Suss MJB3 aligner, an optical microscope, deionized water source, two chemical boxes.

                          


Technology laboratory in Piešťany

Contact info: RNDr. Boháček Pavol, CSc.

The laboratory is based on two high vacuum evaporation systems, clean room facility for photo-lithographic processing of semiconductor wafers to the 3" diameter, and chemical boxes for etching of semiconductor wafers. The laboratory is used to work on research projects related to microelectronics, nanotechnology, and modern environmental sensors and radiation detectors. The layers and thin films are prepared using two different (co)deposition methods – thermal evaporation and electron beam evaporation and patterned by photo-lithography and wet etching.

Equipment:

  • New high vacuum (HV) deposition equipment, model TFDS-462B from VST Services Ltd. with:
  • Scroll pump and turbomolecular pump, 2.5×10-4 Pa in 50 min.,
  • Electron beam evaporation source Telemark TT-6, 4 pocket × 4 cc, 6 kW (750 mA, 8 kV),
  • Two thermal evaporation sources 3.2 kW (8 V, 400 A),
  • Telemark 880 thin-film thickness and rate controller, 6 Mhz, accuracy ±0.5% of thickness,
  • PC interface software communicates with PLC control system through Ethernet port
  • Partially upgraded HV evaporation system with two electron guns and two thermal sources
  • Chemical box for the work with organic and inorganic agents
  • Heating and drying oven up to temperature 300° C for photoresist developing
  • One-side optical mask aligner with optical microscope

               

                                   


Laboratory of Composite Superconductors

Contact info: Ing. Hušek Imrich

Laboratory of composite superconductors is well equipped for the complete manufacturing of composite wirers / tapes and cables.
Rotary swaging, drawing as well as traditional and special rolling techniques (active two-axial rolling, eccentric rolling) are used.
Circular and flat cables consisting from 3-12 strand can be made in the unit lengths of hundred meters.
Heat treatments of powders, metals and composite wires and windings can be done in oxygen atmosphere, vacuum or in the inner gas.

       
    Drawing bench                                 Two-axial roller                   Cabling machine


Laboratory of transport current measurements in superconductors

Contact info: Ing. Kováč Pavol, DrSc.

The laboratory provides characterization of transport current properties of superconductors at variable external magnetic fields, field directions, temperatures and external. It offers DC-transport and pulse current (up to 1500 A) measurements at temperatures 2.7 – 77 K and external fields up to 12 T.

Scope:

  • Characterization of critical currents of superconductors in external magnetic fields
  • Measurements of critical current anisotropy of superconductors at variable orientation of magnetic field
  • Thermal dependences of critical currents in the range of temperatures 2.7 - 77 K
  • Analysis of mechanical stress effects (tension, bending, torsion) in superconductors

                    

The tensile test instrument used for σ(ε) and Ic(ε) characteristics of superconducting wires


Laboratory for X-ray optics and X-ray imaging techniques

Contact info: Ing. Zápražný Zdenko, PhD.

New X-ray laboratory for research, development, and testing of advanced X-ray imaging techniques (free-space propagation imaging, phase contrast, computerized tomography) equipped with micro-focus X-ray sources Hamamatsu, high performance X-ray camera miniFDI (Photonic Science) and high resolution rotary table (Newport) with full developed control software has been optimized (since 2015) also for development and testing of X-ray optical elements within the project "Research and development centre for advanced X-ray technology". The optimization included the following enhancements: anti-vibration optical table, new cover system for X-ray radiation, Medipix detectors with two kinds of read-out chips (Si, GaAs), high-precision manipulators for X-ray optics consisting of two independent hexapods, a new control software allowing free programming (Python) of different types of experiments, resolution test pattern for testing of the spatial resolution down to 0.5 microns (X-radia X500-200-120), Fresnel zone plate (FZP) with a spatial resolution of 120 nm and focusing length of 30 cm (energy CuKα1).

Specifications:

  • Micro-focus X-ray sources with a focal spot size of 8 microns: The source has a tungsten  transmission anode and emits a conical X-ray beam with an output angle of 39 ° allowing geometrically enlargement of the sample up to 140-fold
  • High resolution rotary table (minimal rotation step of 0.0002 °) with a sample holder allowing  to capture sequential tomographic projections
  • X-ray CCD miniFDI camera (Photonic Science). Basic parameters of the camera are as follows: pixel resolution of 1392 × 1040, pixel size: 6.4 × 6.4 μm2, active window: 10 x 8 mm2, scintillator: Gd2O2S: TB3 with an optimal energy response from 5 keV to 17 keV
  • Manipulator for X-ray optics consisting of two independent hexapods with angular resolution of 3.5 µrad and with minimal incremental axis motion (X, Y, Z) of 0.5 μm.
  •  Medipix detectors with two kinds of read-out chips (Si, GaAs). Pixel size: 55x55 μm2, active window: 14x14 mm2.
  • Resolution test pattern for testing of the spatial resolution down to 0.5 microns
  • (X-radia X500-200-120)
  • Fresnel zone plate (FZP) with a spatial resolution of 120 nm and focusing length of 30 cm (for energy CuKα1)

        


X-ray Laboratory

Contact info: doc. RNDr. Dobročka Edmund, CSc.

The laboratory is working within the Consortium for multidisciplinary research of materials MULTIDISC founded by several institutes of SAS. It is equipped with highly flexible diffractometer enabling to perform various types of X-ray diffraction analysis and reflectivity measurements of thin films with thicknesses ranging from micrometers down to a few nanometers.

Scope:

  • Standard θ/2θ and Grazing incidence X-ray diffraction
  • Texture analysis
  • Stress analysis
  • High resolution X-ray diffraction and reciprocal space mapping
  • Quantitative phase analysis, determination of crystallite size and strain
  • X-ray reflectivity and diffuse scattering

Equipments:

Diffractometer Bruker D8 DISCOVER equipped with:

  • Rotating Cu anode operating at 12 kW (max. 18 kW)
  • Goebel mirror providing parallel beam with a divergence of ~ 0.03°
  • Central Eulerian cradle, motorized sample stage with X, Y, Z shifts
  • 4-bounce Bartels monochromator with two Ge 022 channel-cut crystals
  • Pathfinder with a 3-bounce Ge 022 analyzer crystal
  • Knife edge collimator for reflectivity measurement

 

           


X-ray laboratory in Piešťany

Contact info: RNDr. Korytár Dušan, CSc.

Laboratory consists of two working places:

  • X-ray diffrractometer HZG4 and double crystal camera DTS used to test quality of single crystals and for research and development of X-ray optical elements
  • Recently built optical bench for research and development of modern X-ray imaging techniques (free space propagation, phase contrast, computer tomography) consisting of a microfocus X-ray source Hamamatsu, high resolution X-ray camera miniFDI (Photonic Science), and a Newport goniometer with complete developed controls

Raman Spektroscopy Laboratory

Contact info: Dr. rer. nat. Hulman Martin

Raman system by the WiTEC Company uses three lasers with wavelengths of 355, 532 and 785 nm for excitation of spectra. Laser light is a focused on a sample with a confocal microscope which also collects light scattered by the sample. The system uses three spectrometers equipped with CCD cameras, one optimised for each laser line. There is another spectrometer in the system used for luminescence measurements in the optical and near-infrared range up to 2.2 µm

Polarizers and analysers can be inserted in the optical path of the microscope allowing polarisation dependent measurements of Raman spectra. It is also possible to use a part with two Bragg gratings for measuring spectra very close to the excitation laser line down to 10 cm-1.

The system has a motorised table for xyz movement of the sample with a step well below 100 nm. Since the system allows measurement of the spectra with an integration time of less than 0.1 s, it is possible to measure several thousands of spectra in a reasonable time and construct a surface (2D) and spatial (3D) scans of a sample.

                                  


Scanning Techniques Laboratory

Contact info: Ing. Šoltýs Ján, PhD.

Researchers in the Laboratory use both scanning electron as well as probe imaging techniques for complex analysis of physical properties of the surface. The combination of both equipments improves research outputs and extends the possibilities to examine various materials and structures. The laboratory allows scientists to image, characterize and even modify material structures in the range of few millimeters down to sub 100-nm scale.

Scope:

  • Topography imaging of conductive and non-conductive samples
  • Analysis of surface roughness
  • Specialized magnetic measurements with external magnetic field
  • Local anodic oxidation lithography
  • Electron beam lithography

Equipment:

  • NT-MDT NTegra scanning probe microscope (SPM) equipped with complementary probe techniques, including MFM, EFM, SFM and KPM
  • FEI Inspect F50 scanning electron microscope (SEM) equipped with Elphy Quantum lithography software (Raith) and laser interferometric measuring system for precise stage positioning
  • FEG 250 high resolution scanning electron microscope

 

                                  

 


Laboratory of physical property measurements

Contact info: Ing. Kulich Miloš, PhD.

The laboratory provides electrical and magnetic characterization of superconductors, magnetic materials and semiconductors at variable temperatures and external magnetic fields. It enables DC-transport, AC-susceptibility, and VSM-magnetization measurements for temperatures 2.7 – 300 K and external fields up to 14 T.

Scope:

  • Magnetic moment characterization for superconductors, magnetic materials and semiconductors
  • Analysis of susceptibility for variable materials
  • Thermal dependences of material’s resistivity between 2.7 and 300 K
  • Analysis of irreversibility field for variable superconductors

 

                           


Laboratory for electrical characterization of semiconductor structures

Contact info: Ing. Ťapajna Milan, PhD.

The laboratory provides on-wafer electrical characterization of four- and two-terminal semiconductor structures and devices (transistors, diodes, MOS, MIM, and TLM structures). It enables DC and pulse (single and dual channel with minimum pulse width of 40 and 500 ns, respectively) current- and capacitance-voltage measurements.

Scope:

  • DC, pulsed, and transient electrical characterization of III-N and III-V transistors
  • Analysis of resistive switching in MIM structures
  • Reliability investigation of GaN HEMTs
  • Analysis of thermal effects in GaN HEMTs using DC and transient electrical techniques

Equipment:

  • Keithley 4200 SCS (3x SMU, PIV-A, PIV-Q, CVU) connected to Wentworth PML 8000 probe-station
  • Agilent 4284A LCR Meter connected to MDC Hot-chuck with 3x Karl Süss probe-heads
  • Keithley 2400 SourceMeter & Keithley 6517A Electrometer
  • Xe (150 W, 200 – 1100 nm wavelength) lamp equipped with grating monochromator

 

            


Laboratory of electromagnetic measurements

Contact info: Ing. Šouc Ján, CSc.

Measurement equipment designed for magnetization AC losses of superconductors in external magnetic field of magnitude up to 100 mT at variable temperatures from 15.5 K to room temperature with the precise temperature stabilization of 10-3K. 

                                 


Laboratory of dc, low frequency and microwave characterization of superconducting films and weak links

Contact info: RNDr. Štrbik Vladimír, CSc.

The laboratory provides electrical dc, low frequency and microwave as well as magnetic characterization of superconducting thin films structures and weak links in temperature range 4.2-300 K and magnetic field up to 2 T.

Scope:

  • Temperature dependences of resistance
  • Current-voltage characteristics and their derivatives
  • Dependences of critical current on temperature and magnetic field
  • Contact-less determination of critical temperature
  • Magnetic modulated microwave absorption

Equipment:

  • Keithley 224 current source
  • Keithley 2182 nanovoltmeter
  • Ithaco 3961 B two phase lock-in amplifier
  • HP 8350B sweep oscillator
  • HP 8970B noise figure meter
  • HP 8757A network analyzer

                                  


Laboratory of MEMS Device Characterization

Contact info: Ing. Lalinský Tibor, DrSc.

   A fast and precise electro-thermo-mechanical characterization methods are needed to be developed to optimize a sophisticated technology of MEMS devices.
The laboratory as established at the department for MEMS device characterization permits first of all the microchip to be packaged into the ceramic packages using a thermo-compression or ultrasonic bonding technique.  There can be a various protective atmospheres (N2, H2, Ar, forming gas…) including the vacuum used for packaging of the MEMS devices.
Precise dc measurements are performed in the wide temperature range (77 - 1000 K) at various ambient atmospheres using the semiconductor parameters analyzer (HP 4145B). In principle, there are possibilities to measure all the basic electro-thermal characteristics and parameters of the MEMS devices based on electro-thermal conversion mechanism (I-V characteristics, electro-thermal conversion characteristics, transfer characteristics, thermal resistance values, thermal time constant…) in situ at the ambient environment required, so their optimal operating conditions can easily be determined and analyzed. Sensing properties of MEMS gas sensors (sensitivity, selectivity, high temperature sensing ability and sensing time response) can be investigated using a chemical gas chamber (Fig. 1) up to 650 °C.

                                  

Fig. 1.: Chemical chamber for testing of sensing properties of MEMS gas sensors1

Contact: RNDr. Š. Haščík, PhD.


Optical laboratory

Contact info: RNDr. Kučera Michal, PhD.

The laboratory is used to perform optical characterization of semiconductor materials and structures. Standard spectroscopic techniques can be applied at room as well as cryogenic temperatures. Rich information on material electronic properties can be deduced from the spectra, including band-gap width, optical transitions in QWs, crystalline quality, impurity identification.

Scope

  • Photoluminescence is the most important tool for optical investigation of the electronic structure of semiconductors.
  • Photoreflectance is used to evaluate semiconductor band-gap and transition energies in QWs with a good precision even at room temperature.
  • Photoconductivity represents a precise and simple tool to investigate some absorption processes in materials.
  • Transmittance yields useful information especially about properties of band-edge regions of semiconductor energy spectra.
  • Responsivity gives spectral dependences of photo-responses of experimental semiconductor structures, and it indicates their overall performance.

Equipment

  • Sample cooling: optical cryostat with a precise temperature regulation in the 4-300 K range.
  • Pumping lasers: Helium-Neon (633 nm, 10 mW), Argon-ion (488 nm, 20 mW).
  • Broadband light source:  THL lamp 150 W, spectral range 300-2500 nm.
  • Monochromators: Digikrom 240 (CVI Laser Corp., f 240 mm, 500-2800 nm range), MSH-300 (LOT-QuantumDesign GmbH, f 300 mm, 200-2400 nm range), SR500 (Andor Technology Ltd., f 500 mm, 200-2500 range).
  • Detectors: PMT (TE-cooled, 200-850 nm), Si photodiode (400-1100 nm), Ge photodiode, RT (800-1800 nm) or LN2-cooled (700-1500 nm), InGaAs photodiode LN2-cooled (extended wavelength range 700-2600 nm at RT, 700-2250 nm with LN2), PbS photoconductor LN2-cooled (1-4 µm).
  • Lock-in amplifiers: model 5210, EG&G Princeton Applied Research Corp.