The Laboratory provides a wide range of capabilities for both surface modification and analysis. The 3 MV Pelletron Tandem accelerator is capable of implantation at energies above 1.5 MeV and to a maximum energy that depends on the ion charge state, for a maximum terminal voltage of 3 MV. The 1.7 MV Tandetron accelerator is capable of implantation at energies above 0.5 MeV and to a maximum energy that depends on the ion charge state, for a maximum terminal voltage of 1.6 MV. A wide variety of ions can be produced by a Torvis type source, an RF source, a sputter ion source, a SNICS sputter type source and an ECR source. Currents of up to 40 µA of H + (in the beamline) and more than 1µA of metal ions are routinely employed. The implantation end stations operate at pressures in the 10 -7 to 10 -8 Torr range and samples can be either heated or cooled during irradiation. The 400 kV implanter can produce over 50 different ions at energies from 30 to 400 keV. Its end station has stages for implantation at high temperatures down to liquid nitrogen temperature at pressures of 10 -7 to 10 -8 Torr.
Single Ion Irradiation and Ion Implantation
- ion implantation, ion beam mixing, radiation damage
- Ions from gases and sputtered materials
- The Tandem accelerators and the Ion Implanter have the capability of producing a variety of ion beams. Some the beams produced in the Tandems are: H, He, D, O, Ar, Ni, Fe etc.
- The ion implanter can (theoretically) produce beams with any element in the Periodic Table. It is equipped with a very versatile source from Danfisyk – model 921, that can produce beams from gasses, vapors and solids
- For surface analysis more than 200 nanoA of He could be generated. In the implanter currents in excess of 100 microA could be achieve with an Ar beam, and more than 25 microA for most of the other beams.
- Target chamber vacuum
- All the chambers (Tandems and Implanter) achieve a vacuum better than 10 -7 Torr
- Sample temperature control
- Ion implanter: -196°C to 750°C
- Tandems: Multiple experimental stages: Cu stage from RT to 475°C, Ni stage from RT to 650°C and a high temperature stage that can reach 1200° C
- Sample Handling
- Ion Implanter: wafer holder capable of loading five 4 inch wafers or four 6 inch wafers.
- Tandems: rapid interchange device, multiple irradiation stages available for samples switching, and a sample holder that allows higher flexibility in sample orientation.
Dual and Triple Ion Irradiation
- Capability to simultaneously perform dual or triple ion irradiations in the Master Beam Chamber (MBC) located in the South Target Room (STR). Two or all three accelerators can provide a range of ions that could be implanted at the same time with a pre-determined rate and energy. You can learn about these capabilities under the link : ” View Some Possible Experiments” on the menu from the left side of the page
In-situ single and dual beam irradiation with direct TEM observation
- Two beamlines, BL6 and BL are connected to the 300 kV Tecnai Fisher Scientific TEM. BL6 can deliver ions from the 400 kV implanter into the microscope (including 2+, 3+ and 4+ Kr and Xe ions) while BL 8 can deliver low energy H and He beams. These ion beams can be delivered independently or simultaneously into the TEM, for direct observation of radiation damage.
Ion beam analysis
- Rutherford backscattering spectrometry is used to determine the composition profile of the surface to depths of up to one micron and with a resolution of better than 10 nm. The technique provides a determination of the surface composition vs. depth profile and the number of atoms per unit area in the target.
- Ion channeling is a variant of RBS which utilizes the crystallographic nature of the target for the purpose of determining the lattice location of species and the quality of the crystal. Helium ions, accelerated along open channels in selected crystallographic directions return information on the location of interstitial atoms (solutes or impurities), the amount of damage or imperfections in the crystal, and the thickness of an amorphous layer.
- Nuclear reaction analysis is highly sensitive to small quantities of light elements which are difficult to “see” using RBS. The product of a nuclear reaction between the incoming ion and the target atom is used to quantify the impurity level in the substrate or film. Very small concentrations of elements, in the parts per million range, can be detected with this technique.
- Elastic recoil detection, He ions are directed toward a target at a glancing angle, scattering H atoms out of the surface layer. This technique is used to determine the concentration of hydrogen in the surface of the target and is excellent for detecting hydrogen in metal films or the surface hydrogen content of polymers.
Additional facilities associated with the laboratory provide capabilities for a number of experiments:
- Vacuum thermal treatment of implanted samples or films at temperatures up to 1100°C at 1 x 10 -8 Torr.
- Hardness measurements can be performed with one of the recent additions to the lab: a Buehler Hardness Indenter