TQT researchers featured in Microscopy and Analysis

Dr Rebecca Pool

More than a decade ago, a relatively modest facility called Quantum NanoFab, opened to equip Canada-based University of Waterloo researchers with the materials fabrication and characterization tools they needed to develop nanoscale devices. The facility included a $500,000, purpose-built, 975 sq.ft. cleanroom and an e-beam lithography system. Within a couple of years they had added state-of-art thin film deposition and reactive ion etch systems, a surface profiler, thin film mapper and semiconductor inspection microscope.

Fast forward to today, and much has changed. Now called the Quantum-Nano Fabrication and Characterization Facility (QNFCF), the 8000 sq.ft. core scientific research platform sprawls across the University of Waterloo and is home to a mighty 6,750 sq.ft. cleanroom and numerous laboratories for sample preparation, packaging and device assembly, advanced microscopy and additional research activities.

Quantum Nano-fabrication and Characterization cleanroom, Institute for Computing, University of Waterloo.

Prior to Covid-19, from 2019 to 2020, the facility had 32,894 invoiced equipment hours, delivered 3789 training hours and this year, has nearly 300 active lab members. As QNFCF Nanofabrication and Characterization Scientist, Dr Sandra Gibson, says: “We’ve always had the basic fabrication tools but now we’re continuously adding more and more capabilities… We’ve built several satellite labs in the last couple of years alone.”

Gibson joined QNFCF in 2018 following post-doctoral research at Waterloo’s Institute for Quantum Computing with Professor Michael Reimer. Here she was using molecular beam epitaxy, transmission electron microscopy and cathodoluminescence spectroscopy to develop nanowire-based single photon emitters and detectors, critical components for any quantum computer. Her research had been very hands-on and QNFCF needed a ‘Characterization Scientist’ that was familiar with the science behind nanomaterials and could quickly get to grips with the facility’s growing cache of fabrication and analysis instrumentation.

Dr Sandra Gibson, QNFCF

“The moment I saw the position I said ‘that’s me’,” she says. “I think what [QNFCF] did with the facility at the time was very brave – until this point, the facility had been very much a ‘nanofab’ but was now adding more characterization equipment and needed someone with a background in devices.”

“Today our researchers use our tools as a sort of feedback mechanism,” she adds. “They build a device and test it to see if they need to change their fabrication processes or materials – in order to illuminate this process, they really need someone that knows their language.”

Meet the facility
Right now, the QNFCF can only be described as a treasure trove of quantum materials and device fabrication and characterization delights. The all-important clean room contains deposition equipment including atomic layer deposition (ALD), plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD) and physical vapor deposition (PVD) technologies. It also includes etching equipment, such as reactive ion etching (RIE), ion milling, O₂ plasma and wet processing technologies as well as lithography equipment including ultraviolet and electron-beam technologies.

The clean room also houses a host of characterization instrumentation including a Bruker Icon/Fastscan atomic force microscope, and Olympus confocal microscopes. Additional equipment includes an ellipsometer and reflectometers for characterizing thin films, a Leica sample coater, surface profilers from Bruker and Veeco and tools for measuring thin film stresses.

Bruker FastScan AFM.

“It’s nice to have the microscopes in the fab – researchers don’t have to remove samples from cleanroom environment [for characterization]… For example you can go straight from your process into the SEM,” says Gibson. “Researchers are also finding the Dimension ICON AFM very useful.”

But much more lies beyond the main clean room. ‘Satellite’ labs include a sample prep lab, a semiconductor device packaging lab and several dedicated labs at the two Research and Advancement Centres (RAC 1 and RAC 2) with yet more etching, processing, sample preparation and microscopy platforms. Instrumentation includes a Veeco Di Innova AFM, a  non-contact Bruker Contour GT-I Optical Profiler as well as several microscopes including a Zeiss Axio Scope A1.

Meanwhile, the QNFCF ‘Metrology’ Lab currently includes a Zeiss Auriga 40 SEM/FIB for sample preparation and precision micro-milling and is in the process of installing a JEOL JEM-F200 S/TEM with Electron Energy Loss Spectroscopy. “This is going to be directly below our cleanroom and the space is already specified for vibrations,” says Gibson. “The JEM F200 is going to be a real workhorse for us and has EELS which we think is kind of special.”

JEOL JSM-7200 scanning electron microscope at QNFCF.

According to Gibson, the time is right to acquire an electron microscope with EELS as many researchers are developing nanostructures that can no longer be characterized with SEM EDS analysis. “So many of our researchers are now producing devices at a scale of nanometres which means films, interfaces and cross-sections are too small to be characterized using our existing toolset,” she points out. “We’ve been bumping up against this problem and have had to push the characterization out elsewhere but we can now offer an in-house service with EELS taking care of this – devices have been getting smaller and smaller and we’ve had to pivot for that.”

Quantum hot-spot
In 2014, the QNFCF re-located from its original location at RAC1 to the Mike & Ophelia Lazaridis Quantum-Nano Centre, the heart of Quantum Science research at the University of Waterloo. Here research laboratories on superconducting qubits, atomic and ion-trapping quantum information processing, quantum optics, nuclear magnetic resonance and spin-based quantum information processing, and quantum communication and cryptography co-exist, all of which have access to QNFCF.

Indeed, the majority of researchers that use the QNFCF facility are based at the University’s Institute for Quantum Computing and the Waterloo Institute for Nanotechnology with each co-located at the Mike and Ophelia Lazaridis Quantum-Nano Centre. However, Gibson reckons around 20% of users also come from industry, quite often with links to local start-ups that hail from the University.

To date, some 15 start-ups have spun out of quantum research at Waterloo’s Institute for Quantum Computing, including Quantum Benchmark Inc, Aquabits and Q-Block Computing. Gibson also points to micro-LED display developer, VueReal, which has already commercialised a printing platform and micro-LED cartridges. “[VueReal researchers] have been using our facilities very extensively and have just moved to their own fabrication space just down the street,” she says.

Indeed, VueReal was only able to establish itself Ontario thanks to the training and tools offered by the QNFCF – without this resource, the company would have had to relocate to the US to be close to fabrication facilities at Cornell or Stanford Universities.

“We have many researchers working with photonics devices including nanostructures and nanowires but also groups working on batteries, microfluidics as well as diffraction gratings for mass spectroscopy,” adds Gibson.

In recent research, Mohd Zeeshan from the Reimer Group used QNFCF’s tools to fabricate an InGaP/InP quantum dot nanowire device, complete with metal contacts and gates. The device can tune the emission of entangled photons pairs emitted from the quantum dots and holds great potential for quantum sensing, computing and quantum key distribution.

Left: SEM image of an electrically gated InGaP/InP quantum dot nanowire device with potential applications in the fields of quantum key distribution, quantum sensing and quantum computing. Middle: Optical image of the multiple such devices on a 1×1 cm chip. Right: Zoomed-in region of one device. [From Mohd Zeeshan, Dr Michael Riemer Group]

Meanwhile Avi Mathur from the Maheshwari Group has been introducing polystyrene to perovskite films to toughen these brittle materials and prevent the catastrophic failure of perovskite-based devices. Mathur has been using the PeakForce Quantum Nanomechanical mode of the Bruker Dimension Icon AFM to study material properties and is hopeful the modified materials will be used in solar cells, LEDs, next-generation displays and photodetectors.

And in a step forward for scanning probe microscopy, Professor Raffi Budakian and colleagues have been developing silicon nanowires to use as ultrasensitive, high aspect ratio cantilevers. “The researchers are functionalizing the cantilevers with different biofilms and using them for all sorts of  scanning probe measurements – they’ve been using our SEM facilities to characterize these,” highlights Gibson.

Left: Ordered array of Si nanowires, grown on a silicon substrate for use as ultra sensitive cantilevers in scanning probe microscopy. They are grown 7 µm from the edge of the substrate, allowing convenient optical access for displacement detection. Right: A closer look at one of the wires.

So what’s next for the QNFCF? Right now, Gibson is looking forward to a new development, that is currently work-in-progress at the Inert Atmosphere Lab, sited at RAC1. Here, a range of fabrication and characterization instrumentation including confocal microscopy, a Bruker Innova AFM and wet bench equipment, will be integrated within an inert nitrogen atmosphere in a glove box system.  According to Gibson, the glove box set-up spans an entire room and will also be linked to an SEM-based electron beam lithography set-up, electron beam evaporator and a reactive ion etching system.

This latest capability follows growth in 2D materials research at QNFCF, in which inert atmospheric conditions are critical for device development. “These research groups have pushed for this but because of the nature of our facility, any researcher that wants to develop a process in an inert atmosphere could be supported by us,” says Gibson. “This is one great thing about our lab – it’s central to the university and we serve anybody inside and outside of the university.”

“I’m hoping to see the glovebox system also being used by many researchers that are developing sensitive devices,” she adds. “It’s going to be quite something once it’s finished.”