Phenom Pharos Desktop SEM wins Analytical Scientist Innovation Award 2018!

By Rose Helweg - January 18, 2019

The Thermo Scientific™ Phenom Pharos Desktop SEM has been voted second place in the Analytical Scientist Innovation Awards 2018! The microscope—which was introduced in August 2018—is the flagship of the Phenom Desktop SEM product range.

The Phenom Pharos is the first desktop SEM solution from us that includes a field emission gun (FEG). It is easy to operate and incorporates an advanced hardware design for fast time-to-image and simple handling. A wide range of academic and industrial researchers now have access to the benefits of FEG in a desktop model, which can increase their throughput and result in high-quality images and resolution. In addition to providing advanced detectors that can acquire high-quality images with magnifications up to 1,000,000 times, the Phenom Pharos microscope offers researchers:

  • Access to sharp, high-contrast images with resolutions <3 nanometers
  • An intuitive user interface that enables researchers to get a live image in less than 25 seconds after inserting the sample
  • High-resolution imaging that can be obtained simultaneously with analytical techniques

Click here for the full article on the Analytical Scientist Innovation Awards 2018 ›

How to implement an FEG in a Desktop SEM

Scanning electron microscopes are a valuable tool for scientific research and industry. Traditional SEM systems are relatively large and generally more difficult to operate. Desktop SEMs, on the contrary, are smaller, easier to use and their imaging process is significantly faster. Desktop SEMs can usually display feature-sizes ≤10 nanometers, while ultra-high resolution SEMs reach ≤1 nm. This difference is mostly caused by the electron source. Desktop SEMs use compact electron sources like tungsten or cerium hexaboride (CeB6), while ultra-high resolution is only possible with FEGs. 

Using an FEG source: brighter and smarter

The important difference between the two types of sources is brightness. An FEG source is much brighter than a tungsten or CeB6 source, and resolution is directly correlated to brightness: the brighter the source the smaller the spot you can focus while still having enough signal to reach the detectors. A brighter source not only improves the resolution, it also makes the SEM much easier to work with.


What makes it so difficult to implement an FEG in a desktop SEM? 

The answer mainly lies in the vacuum system. To use an FEG, you need to reach very low-pressure levels of 10-10 millibar. Compared to the CeB6-system, this is an increase of the vacuum level of at least 100 times. Such ultra-high vacuum chambers require sophisticated technology, occupying quite some space. A stronger pump alone is not enough to establish such a high vacuum. since water molecules tend to stick to the sidewalls of the column. 

Creating ultra-high vacuum

The only solution for this is heating the column, or ‘baking out the system’. So we had to incorporate heating components into the system and make sure that the most sensitive parts become the hottest since the water always drifts from warmer to colder areas. Yet we had to be careful not to overheat lenses or detectors. Especially in compact desktop SEMs, all these conditions are difficult to meet due to the small column size and because the components are tightly packed together.

Moreover, we want to stick to our successful turbopump system, as it ensures a short sample loading time. In our Phenom Desktop SEMs, the evacuation—or venting process—can be done within 30 seconds. This is several times faster than any other SEM system available to date. In the Phenom Desktop SEMs the sample chamber, the optics and the electron source region are all evacuated by one pump. Therefore, we had to make a considerable amount of changes to the pump and chamber design.

Minimizing vibrations

After having succeeded in generating vacuum levels, which were sufficient for running an FEG, minimizing vibrations became a critical issue. Such disturbances negatively influence the image quality. For example, the turbopump is a rotating component. So the developers had to put a lot of effort into dampening the vibrations generated by this device.

Apart from mechanical movements, electromagnetic fields – both inside and outside – must be shielded too. For instance, the condenser system required for operating an FEG needs to be designed so that it is insensitive to electromagnetic influences. And shielding against all these disruptive factors becomes more difficult the smaller the SEM system is. In addition, the high-voltage board of the new source had to be significantly adapted, including the stability of the high-voltage.

So to get the FEG in our desktop SEM, many changes were required to make the new set-up robust and stable, while keeping it small, easy to use and affordable. In the end, we successfully preserved all the advantages of a desktop SEM and we’re able to improve the resolution to below 3 nanometers.

We were very happy when we started shipping the first machines. Plus, there is something else: the customers are very happy too. Most of them are amazed by the quality of images delivered by such a small machine. And the Analytical Scientist Innovation Award we won with the Phenom Pharos is yet another proof that the first desktop SEM with an FEG is having a positive impact!

Download the Phenom Pharos SEM specification sheet

About the author

Rose Helweg is the digital marketing specialist for the Thermo Scientific Phenom Desktop SEM product range at Thermo Fisher Scientific. Rose is driven to unveil the hidden beauty of the nanoworld and by the performance and versatility of the Phenom Desktop SEM. She is dedicated to developing new relevant stories about high-tech innovation and the interesting world of electron microscopy. And to help potential customers see the possibilities desktop SEM has to offer.

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