We are igniting a new wave of British Industrialism with compound semiconductors

Silicon isn't the only semiconductor that will power the future. To see the invisible, to power high-speed optical networks, and to guide high-energy lasers, you need a different class of materials. You need Compound Semiconductors.

Materials like Cadmium Telluride are transforming how we use X-rays. Zinc Selenide allows defense systems to see in total darkness. Indium Antimonide is key for high-speed electronics and telecommunications infrastructure that moves the world’s data. These are not optional. Any country that wants to lead in aerospace, defense, computing, energy, and medical diagnostics needs reliable and domestic access to them.

We therefore believe that owning compound semiconductor manufacturing is absolutely necessary for economic growth and prosperity.

But the global supply of compound semiconductors is fragile and constrained. We cannot simply rely on importing these capabilities. We must build them. With 1000ºC furnaces and industrial semiconductor processing equipment.

Convergent Labs exists to ignite a new wave of British Industrialism based on this manufacturing reality. We are building a compound semiconductor foundry that the future depends on.

We are starting with Cadmium Telluride (CdTe) to transform the £multi-billion X-ray and gamma-ray imaging industry for medical diagnostics, security and industrial inspection. From there, we will expand our manufacturing base to include Zinc Selenide, Indium Antimonide, Zinc Telluride and other II-VI and III-V compounds. We are building the industrial capacity to forge the next generation of British technology.

And we will be doing it in the North East. Standing alongside the region’s established players, we signal the emergence of a new and resilient British industrialism.

Next-generation

X-ray imaging

To understand the way that compound semiconductors are transforming the world we live in, a good place to start is in X-ray imaging. Semiconductors are enabling a shift in X-ray from 2D, blurry and grey to 3D, high-resolution and in colour. It is a dramatic transformation that allows us to see and identify things we previously couldn’t. And this heralds a new era for healthcare, defence, security, manufacturing and industrial non-destructive testing.

Before we look at what this shift means, let’s take a step back to understand a bit more about how X-ray imaging works. Why do we want to use X-rays in the first place? X-rays help us see what is inside something, without opening it up. This is important for not only medical diagnoses to detect tumours or diseases but also security (to make sure there aren’t any explosives in your bags) and industrial inspection (to detect food contaminants in a factory, for instance, or to ensure that a lithium-ion battery has been assembled properly). In fact, there is a very long list of use cases for X-ray imaging, and the market is worth well over $10 billion annually.

X-ray images are created by basically blasting X-rays (a type of radiation) at an object or a person’s body. Some of the X-rays will get through, but others will be absorbed either partially or completely depending on the density of objects like metal, bones, organs, tissues, plastics, etc. A special detector plate on the other side gets hit with the X-rays that get through. The detector helps convert the X-rays into an image that we can look at. Maybe you or a family member have had a CT scan and you are familiar with the types of images it produces.

The detector plates most commonly used today can't actually "see" X-rays. They use what is called scintillator-based technology, which means it has to first turn the X-rays into visible light and then convert that visible light into an electric signal, which is subsequently used to create the image. In industry parlance, this is known as “indirect conversion”. What this means is that by the time the electric signal gets through, a lot of the detail is lost and the image isn’t very good. It takes time too, so you can’t get lots of images in quick succession, which is critical in a factory setting. In the case of medical imaging, you also have to blast the patient with a lot of radiation in order to get a usable image, which is far from ideal considering the health risks of radiation exposure.

Indirect conversion technology isn’t bad, and we derive a lot of value from it today. In fact, there are well over 10,000 indirect conversion CT scanners sold annually, and CT remains a very common technique for medical imaging, security scanners, radiation threat detectors and other industrial applications around the world. But the technology could be a lot better. And if it were better, it would have significant real-world benefits and advantages. Today, when doctors see a tiny speck on a lung or a heart vessel, they might not be able to tell whether it is a blockage, a tumour or just a shadow on the picture. And they need to make decisions based on this information which have long-term life changing impacts for patients.

Fortunately, the technology is about to get better. A lot better. How? By enabling ‘direct conversion’. Direct conversion means that each X-ray photon that hits the detector is converted, directly, into an electric signal. This is why the industry calls this new approach “photon counting”, because each photon is detected or “counted”. So, when you hear photon counting, think of direct conversion. What this means is that the image is much higher resolution and much more detailed. Another cool thing about photon counting is that, because every one of those X-ray photons also carries a specific "energy" level, we can now detect colour. So now, with direct conversion / photon counting, we don’t just get a better image, we can see differences in colour and also, crucially, get it with lower radiation exposure and in a faster time.

Here’s where

compound semiconductors come in.

Ask yourself, what is enabling the shift to direct conversion? The answer is: a new form of detector made from a compound semiconductor called Cadmium Telluride.

And we are manufacturing it.

Cadmium Telluride is a strange but wonderful material. When you hear the word “semiconductor,” you probably instantly think about silicon and computer chips. But Cadmium Telluride is also a semiconductor. And a pretty unique one, too.

It is actually two different metals (Cadmium and Tellurium) fused together in a special furnace into what we call an “ingot” or a “crystal”, which is then expertly sliced and diced into thin wafer shapes. A semiconductor is a material that sometimes conducts electricity and other times doesn't. It’s like a light switch stuck in the “off” position until it gets a specific kick which makes it conduct. With Cadmium Telluride, the kick comes from X-rays. When an X-ray hits a Cadmium Telluride detector, it crashes into the atoms so hard that it knocks a bunch of electrons loose, and we can “pull” those loose electrons using an electric field.

Cadmium Telluride is a key enabler for direct conversion, but it isn’t the only thing that is needed. OEMs and leading technology companies in X-ray imaging have invested heavily in their own proprietary electronic systems, read-outs and algorithms to derive the most value from these new detectors. Every industry from medical imaging to security scanning to industrial inspection has placed its bets firmly on this new technology platform.

But the perverse thing is that they have made these commitments without securing the supply of the Cadmium Telluride itself. Today, there are only 3 companies capable of making it to any relevant industrial-grade. It is very, very hard to make Cadmium Telluride detectors. Currently, there isn’t a supplier in Europe capable of meeting the industrial demand.

Why is it so difficult to manufacture Cadmium Telluride? The answer is that it requires expert knowledge in a 3 different disciplines; firstly, the process of “growing” the Cadmium Telluride itself in 1000ºC furnaces, secondly, the semiconductor physics required to equip the material with the ability to “detect” X-rays and, thirdly, the knowledge and expertise to integrate the detector into the customers’ imaging devices and proprietary electronics. None of this knowledge is commoditized and none of it is straight-forward. There are overlapping scientific and engineering challenges which only a handful of people around the world have overcome. Many companies have invested significant amounts of time and money to develop their own Cadmium Telluride capability, but have been unable to bring together the right expertise.

And the same issues come up everywhere you look in compound semiconductors. Despite the talk around supply chain resiliency, geo-politics and defence, our access to critical materials looks increasingly fraught.

So this is the immediate gap that Convergent Labs is addressing. We have assembled a team of experts with industry-leading experience in Cadmium Telluride and photon-counting detector manufacturing. We are deploying our own furnace designs to grow Cadmium Telluride ingots, and we will process the ingots into detectors for next-generation X-ray imaging systems.

But the opportunity doesn’t stop at Cadmium Telluride. Our vision is to be a specialist compound semiconductor manufacturer for other II-VI and III-V semiconductor materials like Zinc Selenide, Indium Antimonide, Zinc Sulfide and Zinc Telluride that are used in key industrially strategic areas like laser optics and infrared imaging as well as X-ray and gamma-ray imaging.

The rationale for a UK domestic compound semiconductor manufacturer could not be stronger in the current economic and geopolitical climate.

Our ambition is to be a global compound semiconductor powerhouse, and ignite a new wave of British industrialism based on engineered scientific capabilities that ensures Britain can forge a leading role in 21st century technology.