Nanofabrication Nottingham
Nanofabrication Nottingham
The Nanobeam nB5 EBL instrument available at the nmRC
Nanofabrication Nottingham
Nanofabrication Nottingham houses a wide range of nano- and microfabrication equipment from state of the art lithography systems to deposition and etching equipment.
The equipment is either located in the electron beam lithography (EBL) cleanroom in the nmRC or the microfabrication cleanrooms in the Physics building. The wide range of equipment supported by a team of experienced technicians allows for a variety of workflows to be completed in house without the need to outsource work. Full training is available or we are able to complete work for users both internal and external.
For details of our charges for external users please click here. For more details contact Richard Cousins.
Key Features
- Processing of substrates from 5mm chips to 3" wafers
- Deposition of a wide range of metals and dielectrics
- Etching of materials via wet or dry etching
- Thermal processing of samples
- Thickness and optical measurements
- Packaging and measurement of devices
Nanofabrication Nottingham Facilities
Electron beam lithography
- Nanobeam nB5 EBL tool located in class 4 cleanroom in the nmRC.
- 80KV beam with variable current allowing both quick write speeds and high resolution.
- Features as small as 50nm possible.
- Alignment accuracy of <20nm possible with use of alignment marks.
- Substrates from 5mm up to 3" in size including holders for coverslips.
- Fast and automated writing system.
Photolithography
- 2 mask aligners suss MJB3 and MA-6 Gen 3 for use where the same design is used repeatedly.
- Maskless lithography (Alvéole primo) for use where pattern needs to be varied between exposures.
- Resolution from 0.7µm (MA-6) to 1.2µm (Primo).
- Optical alignment of layers, backside alignment via IR camera on mask aligners.
- Substrates up to 3" can be exposed.
- Resist thickness up to 50µm.
Thin film deposition
- A range of thermal evaporators for depositing of thin (sub-micron) metal films e.g. Cr, Ti, Au, Ge, Zn, Ni and Al.
- Electron beam evaporators for dielectrics and metals that are hard to thermally evaporate e.g. Pt, Ni, Si, Sio2 and Pd.
- Sputter coaters for thin films e.g. Au, Ir, ITO.
- Corail D250 Plasma enhanced chemical vapour deposition (PECVD) for depositing dielectric films e.g. aSi, SiNx and SiO2.
- Electroplating of copper and gold.
Etching
- Corail 200Il plasma etcher capable of reactive ion etching (RIE) and inductively coupled plasma (ICP).
- Chlorinated and fluorinated gas chemistries allow for etching of Si, SiO2, GaAs, Al, photoresist and many more materials.
- Etch depth monitoring via laser interferometer.
- Mantis Deposition Ltd Ion beam etcher including spectrometry end point detection.
- Fully stocked wet etch fume hood for acid etching of numerous materials.
- Includes capability to etch with hydrofluoric acid.
Sample Prep and heat treatments
- Laminar flow cabinets with spinocoaters for application of resists and thin films.
- Plasma cleaners which can also be used to activate glass surface for PDMS bonding for microfluidics.
- AnnealSYS rapid thermal processor for annealing samples.
- Carbolite Gero tube furnace and purged hotplate for controlled heating of samples.
- Dicing equipment and wire bonders for back end processing.
Characterisation
- Accurion EP4 elipsometer capable of measuring optical properties and thickness of thin films with a lateral resolution of <5µm.
- Woollam M2000 variable angle spectroscopic elipsometer (VASE) capable of making optical measurements between wavelengths of 190-1700nm.
- Tencor D-120 stylus profile capable of measuring steps from 10nm-800µm.
- Reflectometer for measuring optical properties and thickness of thin films.
- Optical microscopes with magnifications up to 1000x and a range of measurement methods e.g. brightfield, darkfield and DIC.
- Wide range of SEM and TEMs located in the nmRC.
Cell patterning
- Alvéole Primo system attached to a Leica DCiM inverted microscope.
- Allows for seeding of cells into particular area of substrate.
- Can be used to selectively deposit cells into the centre of TEM grids avoiding the possibility of cells being on metal support.
- 2µm resolution with patterns being supplied in simple TIFF or PDF format.
- Number of fluorescent filters to check exposures.
Research Highlights
Gold on glass nanostructures
There are many applications where it is necessary to pattern metallic (such as gold) structures on a substrate such as silicon or glass. In Nottingham we are able to pattern features as small as 50nm on a range of substrates including insulation substrates like glass. This is done by applying a resist on a glass coverslip followed by a spin on conductive coating. EBL is then used to define a pattern from a GDSII file. After development the sample is coated with a titanium or chrome adhesion layer followed by gold, the metal sticks to the sample where it has been exposed and the resist where it wasn't. The sample is then placed in a solvent removing the resist leaving metal only where the resist was exposed.
Moth eye mould
Anti-reflection coatings can be made by replicating the design found on moth's eyes. These consist of a series of cones, we are able to etch this design, or the inverse onto a piece of silicon (in the case of the inverse this can be used as a mould for stamping).
EBL is used to define a pattern in a resist, for cones a series of circles are patterned or the inverse can be patterned for holes. This resist in then used as a mask for the etching step.
To etch the pattern the sample is placed in a dry etcher which uses an ionised gas to etch the sample. By varying the recipe we have control over the sidewall angle allowing for pillars or cones to be made.
Microfluidics
Whilst there are numerous sellers of standard microfluidic chips occasionally there is a need for bespoke designs. Using our maskless lithography tool we are able to quickly make master stamps that can be used to make microfluidic chips. Design files can be supplied in PDF or TIFF formats and patterned into CAR44 resist (similar to SU8) which can then be etched into silicon to create a more robust stamp. PDMS can then be mixed and poured onto the chip before being outgassed and cured. The PDMS is then peeled off the stamp and placed with a coverslip in a plasma cleaner where it is exposed to an oxygen plasma activating the substrate. The PDMS and glass are then pressed together forming a permanent bond.
Elipsometry
By combining our EBL facilities with our imaging elipsometer we are able to accurately measure flakes of 2D materials such as InSe or hBN. The first step is to deposit location marks onto a suitable substrate via EBL and thermal evaporation. These can be used to map a particular flake of interest that had been identified earlier (e.g. by AFM, optical microscopy). The Accurion ep4 can then measure this flake and extract its thickness and optical properties.