Micro- and nanotechnologies for industry applications

Transcription

1 Kaunas University of Technology Institute of Physical Electronics Micro- and nanotechnologies for industry applications Sigitas Tamulevičius Savanorių pr. 271, LT-3009 Kaunas, Lithuania Tel./fax: Tel.:

2 Structure of the Institute Departments Microlithography Vacuum processes Physical and chemical analysis Staff: 30 employees Prof. Dr.Habil. -1, Dr.-10 Research of thin films and surfaces

3 Major research activities Surface micro- and nanometric structures: thin films and surface engineering (physics and applications) application of ion and plasma methods for formation of nanostructures and nanomaterials Optical document security: micro-optical elements, interference filters development of new materials and structures

4 Partners EU research institutions: Helsinki University (Finland) Kiel University (Germany) Poitiers University (France) Main industrial partners: Ekranas Brown Sharp Precizika Vilniaus Ventos puslaidininkiai Lithuanian research institutions: Vilnius University Institute of Chemistry Institute of Textile Lithuanian University of Agriculture Subdivisions of KTU Institute of Physical Electronics in collaboration with the Service of the Technological Protection of the State Documents implements the newest technologies of document protection in Lithuanian enterprises and state institutions

5 Scientific projects and budget Completed research projects: Project Thin layers and surface nanometric structures - total budget Lt Lithuanian State Science and Studies Foundation projects: Mechanical properties of multilayer structures - total budget Lt New junctions for spintronics - total budget Lt Investigation and analysis of residual gas composition in color picture TV tubes - total budget Lt Environmental research projects carried out with University of Agriculture - total budget Lt Institute is continually carrying out research in the field of optical document security Implementation of new technologies and analytical services during the year Lt

6 ! International projects: Mechanical properties of multilayer free standing films (together with Poitiers University, France and KTU) total budget FRF Nordic Energy Research Program (together with Risø National laboratory, Oslo University and KTU) total budget NOK! NATO CLG (NATO Science Programme - Cooperative Science and Technology) "Nano-structured functional coatings for optical and lubricating applications EURO! FP6 "Micro and Nanotechnologies going to Eastern Europe through Networking" Proposal No: (Programme - Integrating and strengthening the European, Research Area, identifier: FP ACC-SSA-GENERAL) EURO

7 ! International projects: FP6 project COOP-CT "Nanoimprint lithography for novel 2 and 3 dimensional nanostructures" (3D NANOPRINT). EURECA project E!3444-EULASNET-ULCOP "The New Technology Of Roll Production

8 Analytical facilities Spectrometry X-ray photoelectron X-ray fluorescent Atomic absorption Quadruple mass Optical emission Infrared Ultraviolet / visible

9 Analytical facilities High pressure liquid chromatography Gas chromatography Thermal analysis X-ray diffraction Ion selective potentiometry BET surface analysis Scanning electron microscopy Optical microscopy Image processing Laser ellipsometry Analysis of electrical characteristics of materials and devices

10 Lateral force 3D images Al on Si(100) CdS on Si(111) Atomic Force Microscope NT-206 Basic scanning unit CdS topography Supports operation of the AFM in following modes: - Static (including contact mode (of topography) and lateral force microscopy) - Dynamic (including non-contact and intermittent/analogous to Tapping Mode / mode) - Static/ Dynamic force spectroscopy. Characteristics of AFM: maximum scan field area: up to 30x30 µm; measurement matrix up to 512x512 points and more; maximum range of measured heights: 4 µm; lateral resolution: 2 nm, vertical resolution: nm; scan rate: 10 µm /s in X-Y plane.

11 Technological facilities Plasma enhanced chemical vapour deposition Direct ion beam deposition Plasma spray deposition Magnetron evaporation E-beam evaporation Thermal evaporation Reactive ion etching Ion beam etching Optical lithography Holographic embossing Langmuir - Blodgett films deposition system

12 Interference, imprint lithography and reactive ion etching Thermoplastic polymer is used for micro and nanorelief formation by mechanical imprint followed by reactive ion or wet etching Periodical micro- and nanostructures in Si are formed by combining superposition of the picosecond pulses of YAG:Nd 3+ laser (355 nm) and reactive ion etching of the Si in RF plasma This method is used for the production of photonic crystals, diffractive optical elements, precise spectral devices and positioning systems

13 Schottky contact based gas sensors Operation principle of the Schottky barrier gas sensor: Typical constructions of gas sensors Schottky diode Metal-insulator-semiconductor (MIS) structure Field effect transistor with catalytic gate Advantages of the Schottky contact based gas sensors: High sensitivity (below 10 ppm for some gases) Short response time (in range of few miliseconds) In-situ measurements Possibility perform measurements both at low (GaAs) and high temperatures (GaN, SiC) Innovation: Sensitivity and selectivity can be increased using semiconductor surface treatment (chemical, ion beam, plasma)

14 Synthesis of diamond-like carbon films Methods: direct low energy ion beam deposition from C 6 H 14 and H 2 gases mixture reactive hibride vacuum evaporation Properties of the coatings: high electrical resistivity, transparence for visible and infrared light (60-90 %), chemical resistance, hardness and wear resistance (10-80 GPa), thermal conductivity (4-18 W cm -1 K -1 ), radiation resistance Possible application areas: coatings for sensors and micro-electromechanical devices passive layers in microelectronics wear and chemical resistant protective coatings for industry and biomedical applications

15 Diamond like carbon coatings for the nanoimprint lithography Technological steps: silicon patterning and deep RIE (SF 6 +N 2 plasma chemistry). Synthesis of DLC coating Hot imprint and freezing Master separation AFM image (3D and 2D) of silicon pits (horizontal mark size 5 µm, vertical mark size 125 nm). O 2+ ion beam treatment Deep RIE of silicon pits

16 Nanostructured films applications: photonic crystals, high capacity and density computer memories, semiconductor lasers, biomedical devices (membranes and sensors) Nanostructured self-assembling of thin films Forming of periodical (tens to hundreds nanometers in diameter) one or few layers (3D) structures or nanotubes Formation is based on thermocapilar convection in colloidal solutions, PS and PMMA blends on crystalline silicon (100) substrates

17 Periodic polymer based structures Master matrix production and evaluation Silicon (100) Silica Replication UV hardening Imprint Silicon matrix in photopolymer (UV) silica matrix in photopolymer (UV) silica matrix in photopolymer (Imprint)

18 Periodic polymer based structures 3,5 3,0 Diffraction efficiency, % 2,5 2,0 1,5 1,0 0,5 2 0 Test- quartz glass Quartz glassreverse Photopolymer replica Replica to photopolymer on PMMA 0,0 0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 0,40 0,45 0,50 0,55 0,60 0,65 0,70 0,75 0,80 0,85 0,90 Ridge width, r.u. The dependence of diffraction efficiency on the ridge width of periodic structures (quartz glass master-matrix, imprint to photopolymer on PMMA, photopolymer replica and quartz glass master-matrix reverse)

19 Wavenumber (cm -1 ) FT-NIR transmission spectra and SEM photograph (mark size 10 microns) of pyramidal photonic pillars after 2,5 min etching in water solution of hydrazine at the different angles of incidence Microphotonic structures in Si 14 Transmittance (%)

20 Microrelay Substrate - Si Cantilever - Ni/Au Sacrificial layer - Cu Technological steps: #Patterning, #E-beam evaporation Cr (30nm), Au(200nm), Cu - 2µm Threshold voltage 20 V #Patterning Contact resistance less than 1 #E-beam evaporationohm Au (200nm) Ni (2 µm ) #Chemical etching Current 5-10 ma Frequency 100 khz

21 Polymeric discs and scales for positioning systems Periodic structures (d=40µm) are formed on the Si(100) substrate by optical lithography and reactive ion etching using mask (70nm layer of quartz+fe 2 O 3 ). Replication of the periodic structure in polyacryl is made. Replica is metallized by evaporation of Al Final product is PET+photopolymer+Al layer 80 nm. Cheap and productive method for the forming of diffraction gratings in the polymeric tape by hot embossing are developed.

22 Optical document security Design and production of optically variable devices (OVD) for the state institutions and commercial structures High technologies and unique analytical methods like micro-lithography, ion and plasma processes, vacuum coatings, scanning electron microscopy, X-ray photoelectron spectroscopy are employed for the production of OVDs

23 Optical document security OVDs are the periodic surface structures on a thin polymer film with a period close to the length of visible light. Identification of OVDs is based on specific kinegram movements due to diffraction of the reflected light. Additional security features: micro- and nanotexts, laser marks, means against reuse Patent of the Republic of Lithuania No.4281: V. Grigaliūnas et all. Diffractive structures in the multi-layer

24 Measurements of substrate curvature by laser interferometry The double-beam differential laser interferometer The Michelson interferometer δ = ( ) t δ λ n, 2

25 σ, GPa -0,01-0,03-0,04-0,05-0,06-0,07-0,08 Thermal stress in diamond-like carbon films ,02 σ T T, C d dt MPa = 2. 9 o C The dependence of the stress variation with the measuring temperature (Thickness of film 400 nm, substrate temperature during deposition 300 C) σ = σ + σ f dσ dt ( ) in th σ = + = E f α s α f in dσ dt th dσ dt ( )( T T) σth = Ef αs αf 0 σ th dσ = ( T T0 ) = dt 0.81GPa T 0 the temperature of process, T the room temperature. σ in = σ σ f th = 0.67 GPa

26 The prism interferometer R ( 2 l l ) 2 k n = λ ( k n) l k, l n - radii of fringes n,k - number of fringes, λ =2 h, n - prism refraction index, Θ - angle of incidence of light. h = λ 1 2 n 2 2 π sin sin 4 arcsin Θ n 1 2

27 Residual stress dependence for the SILAR grown CdS films on (100)GaAs versus thickness of the film G. Laukaitis et al. / Applied Surface Science 7538 (2001) Stress, (N/m 2 )x CdS thickness, nm H 2 O rinsing H 2 O rinsing Cl - Cd 2+ or Zn 2+ S 2- Na + Cd 2+ (aq.) +2Cl - (aq.) + +2Na + (aq.) +S 2 (aq.) CdS + Na + (aq.) +2Cl(aq) 0.1 M CdCl 2 (ph 5.8) and 0.05 M Na 2 S (ph12.5) - the precursors

28 Optical schemes for the Electronic Speckle Pattern Interferometry Interferometer for the measurements of tangential displacement d τ = λ 2sin θ ( 2) The measuring sensitivity Interferometer for the measurements of normal displacement d n = λ 2cos θ ( / 2)

29 Mechanical properties of thin film and structures (Electronic speckle pattern interferometry) d 0 Object plane y1 x A Σ z Φ d 1 i Lense p( ζ,η) η Diameter 2R ζ Image 0 y plane x A' z y, mm Speckle pattern processing, Speckle pattern analysis, Microtensile experiments, Freestanding films x, mm

30 Testing of mechanical properties of thin films displacement of the moving grip up to 70 µm; displacement resolution 50 nm, maximum tensile rate 150 nm/s, maximum tensile force 2.5 N; force resolution N; optical analysis area mm 2.

31 Testing of mechanical properties of thin films ESPI Piezo-actuated tester

32 Main technological steps: Production of free-standing films double-sided masking (SiO 2-600nm) and UV exposure (photoresist Shipley Microposit S1805), 1.5 mm reactive etching and wet chemical etching (N 2 H 4 :H 2 O) through the silicon wafer. Possible free-standing films (thickness µm): metallic (Al, Ti, Ni, Cu), 2 mm 1.5 mm dielectric (SiO 2, TiO 2, Si 3 N 4, diamond like carbon, α-sic:h, α- CN:H), multilayer structures etc. SEM photograph of the free-standing aluminum film. (Mark size 1 mm)

33 Plasma spray applications Seawater activated batteries H 2 O + 2e - = H 2 + OH 2 HCO 3 + 2e - = H 2 + 2CO 3 2 Mg + 2H 2 O = Mg(OH) 2 + H 2 Thin films of yttrium stabilized zirconia, and their interfaces formed towards other SOFC materials

34 Research toward solid oxide fuel cell Plasma spray deposition of yttrium stabilized ZrO 2 powders, prepared by different ways Porous anode production Production of complete fuel cell in one process. Air N 2 Catode Electrolyte Anode o 2- o 2- o 2- o 2- o 2- o 2- o 2- o 2- + External circuit - Gas (CH, H, CO) H 2 O, CO 4 2 2