Material Fabrication

  • Electron Beam Lithography system.
    A new important addition to the scanning microscope: the Electron Beam Lithography system provided by  RAITH  will allow to fabricate miniaturized functional device for testing and characterization.
  • Two magnetron sputtering plants (one brand new) in a clean room (class 100) able to perform DC and RF sputtering and equipped with loadlock systems to introduce and extract the samples without breaking the vacuum.
  • A homemade plant for a controlled thermal co-evaporation and co-sputtering equipped with cryogenic pump.
  • Three furnaces for thermal oxidation in dry or humid air and treatments in inert atmosphere. Two microwelders for wire bonding and packaging of sensors one based on local welding and the other a brand new Kulicke & Soffa wedge bonde
  • Experimental set-up for electrochemical anodization
  • A Precision Spin-Coating System provided with a Programmable Logic Controller
  • Plasma cleaning system
    13,56 MHz High Frequency generator
    Chamber size: diameter 100 mm, lenght  260 mm.
    Two gas inlets
    Totally controlled by microcomputer.
  • Two stations for ageing of the sample


Electron Beam Lithography system

ELPHY Quantum lithography system - 2.5 MHz dual DAC addressing
- 2 high speed 16-bit DACs for X and Y main beam deflection
- active deglitch circuit, selected for low temperative drift
- 6 multiplying 16-bit DACs for overlay alignment and write field calibration
with sub-nm step size control
- high speed image acquisition & mark registration (400 ns Video ADC)
- beamblanker control circuit TTL 5V

ELPHY Pattern Generation Software Suite in 32 bit architecture
- multi-user Environment with separate files and parameters for each user
- hierarchical GDSII CAD editor with large file handling capability
- data import formats DXF, ASCII, CIF, etc
- extensive task list generation with SEM or FIB remote control
functionality (for most digital SEM or FIB)
- automation package for step and repeat exposure mode
- pattern alignment, user assisted, fully automated
- fast image acquisition with zooming and overlay techniques
- integrated metrology functionality
- user specific automation capabilities using Microsoft Scripting language
- job control functionality with parameter and system information logging
- 2nd software license for off-line data preparation


Sputtering and evaporation plants

Kenotec sputtering plant

Two vacuum chambers make up the sputtering plant, the working chamber devoted to the deposition and the load lock chamber where we can introduce the substrates without breaking the vacuum of the operating chamber. The substrates can be heated also in the load lock chamber in order to desorb the undesired species adsorbed on them.

A turbomolecular drag pumping station TMH 064 D E produces the vacuum in the load lock chamber: it is composed of a turbomolecular pump, a diaphragm vacuum pump and an electronic drive unit. The pumping speed for Nitrogen is 30 l/s, the working range from 1000 to 10 -8 mbar, the weight 12 Kg.

A rotative and turbomolecular pump produce the vacuum in the working. The first is a Edwards Rotary vane pump RV12, the maximum displacement is 17 m 3 h -1 and maximum pumping speed is 14.2 m 3 h -1 , the maximum permitted inlet pressure is 0.5 bar and the maximum permitted outlet pressure is 1 bar, the ultimate total pressure is 2 10 -3 mbar. The second is an Elettrorava 160/450 turbomolecular pump 450 l/s.

Five different positions can be selected in the working chamber, one for the etching process and for the substrates introduction and the other 4 positions for the targets with DC and RF power supplies. The position of the samples is controlled by a step by step motor by the PC. During the deposition oscillation between two targets can be made in order to deposit layers of different materials.

The power supplier are an advanced energy MDX 1K Magnetron drive and 2 each advanced energy RFX 600 generator with 2 advanced energy ATX tuner one for the etching process and the other for the deposition.

The advanced energy MDX 1K Magnetron drive characteristics are: 12A nominal @ 1KW (full power) as input current, 0-1000W as output power and 0-1000V. 1500V open circuit voltage as output voltage, 0-1 A as output current. Each advanced energy RFX 600 generator is a two stages power generator using a Fetpower modular power amplifier and a switchmode dc power supply for main power and control. The RFX is designed for 80% reflected power capability. It regulates output power using either forward power or dc bias of the load. The characteristics are: 600W maximum power into a 50 Ohm load, 13.56 MHz as output frequency, 50 Ohm as output impedance. The advanced energy ATX tuner characteristics are a power capacity of 600, 1250, 2500W, an impedance range of 5 to 2000 Ohm.

The are two lines for the inlet of gas, the flux and the pressure are controlled by 2 MKS Type Mass-flow® controller with a MKS Baratron® type 622 for the pressure measurements. The depositions can be made in Argon or in a reactive atmosphere, the substrate can be kept at constant temperature in the range between RT and 450°C.There is also a IL150 Quartz Crystal Rate Monitor to measure the thickness of the deposited layer.A PC application developed in visual basic allows a complete remote control of the systemFigures A and B reports the synoptic of the application that drives the sputtering system: we can observe the interface of the program controlling the sputtering system, where we can operate in a very simple way to prepare everything for the depositions.

Alcatel 350 magnetron sputtering

Magnetron sputtering and evaporation plant



Metal oxide nano-crystals are prepared according to the recently proposed evaporation-condensation (EC) process, with Vapour-Phase (VP) and Vapour-Liquid-Phase (VLS) growth mechanism. Such a deposition technique consists of thermally-driven evaporation of bulk metal oxides followed by condensation.

The experimental set-up for the oxide deposition consists of an alumina furnace capable to achieve as high temperatures as 1500 °C, in order to activate decomposition of the oxide and to promote evaporation. The controlled pressure of the inert atmosphere and the gradient of temperature within the furnace allow condensation and nucleation of the nanostructures downstream the gas flow.

The pressure, the gradient and the carrier flux have to be strictly controlled in order to guarantee the reproducibility for deposition. During the temperature transients (from room temperature to evaporation temperature and back to RT), inert-gas flows in inverted direction (from the substrate to the powder source) to avoid uncontrolled condensation over the substrate.

When the VLS growth mechanism is preferred, the growth catalysts are deposited by sputtering or by solution dipping using commercial available nanoparticles dispersed in a colloidal solution.

At SENSOR there are three systems equipped for the preparation of nanowires, all of them controlled by custom LabVIEW VIs.


Electrochemical anodization

Electrochemical anodization method is used for the preparation of metal oxide nanostructures at room temperature. Nanotubular and nanoporous structures of TiO2 are possible to obtain by means of electrochemical anodization method. By anodization also is possible preparation of different metal oxide nanostructures from different clean metals and alloys (Zn, Fe, Ni, Nb, Al…).   Anodization is carried out in hood equipped with the cleaning and drying system for the samples (Figure 1).

Figure 1. Hood equipped with the cleaning and drying system.

A two-electrode cell is used for anodization (Figure 2). Magnetic stirring (Figure 3) is used for preparation of anodization electrolytes.

Figure 2. Scheme of electrochemical cell.             Figure 3. Magnetic stirrer.

Anodization is performed by constant voltage or by constant current mod using a power supply (Figure 4). Power supply interfaced with a computer. Voltage, current and anodization time are controlled during the anodization process (Figure 4).

Figure 4. Power supply Delta Elektronika SM 300-5 interfaced with a computer