Thin film Metrology

For film film metrology, we currently use Spectroscopic Ellipsometry, Spectral Reflectance and Grazing Incidence Interferometry. For very thin films we use a Woolham M2000 Spectroscopic Ellipsometer which has nm resolution. This system is equipped with a fully automated variable angle wafer mapping stage, including a laser focus option for automated focusing in the Z direction which can also be used to characterise wafer bow.

For fast measurements we often use a Filmetrics F20 Spectral Reflectance system which has resolution down to 20 nm. We also have a transmission option for this as well as a basic uv-vis (Genysys 10S).

For general wafer bow observations we use a Logitech GI20 grazing incidence interferometer. The image below shows an example of a flatness measurement of a 2” wafer. The fringes on the screen on the bottom right represent 2µm, thus it is trivial to calculate the wafer bow. This system is predominantly used to monitor wafers whilst compensating for bow with a CMP chuck.

Above left:  Woolham M2000 Spectroscopic Ellipsometer with wafer mapping stage for fully automated multi angle, multi wavelength mapping of up to 6” diameter wafers.

Above right: Logitech GI20 Grazing Incidence Interferometer for real time wafer bow characterisation up to 4” diameter.

Right: Filmetrics F20 Spectral Reflectance / Transmission system, with microscope optics.

Low temperature characterisation

For routine low temperature measurements between 2-350 K we operate an Evercool II Physical Property Measurement System (PPMS) from Quantum design (below right). Funded by our ERC consolidator grant. This system includes a 9T magnet with DC Magnetism, AC Susceptibility, Resistivity, Vibrating Sample Magnetometer etc. We have extended its electronics for Hall effect and device measurements (such as MEMS / NEMS) at low temperatures.

This is extended by access to a shared departmental dilution refrigerator (BlueFors 7mK, below; close up of sample stage below right) capabilities for low temperature characterisation of our superconducting diamond. As well as these standard options we have multiple custom measurement options built in house.