We recently sat down with Adam Khan of Diamond Quanta – the company that wants to replace the silicon chip with ones made from diamond. We discussed the reason for this glittering idea, the challenges it presents, and the implications of the technology.
The past half century has seen a fantastic evolution in electronics and computers thanks to the silicon chip. In line with Moore's Law, the number of transistors on a single chip doubled roughly every two years with a commensurate rise in computer power and drop in prices. The result is our modern age of handheld supercomputers, increasingly common AI, the internet, and all the other things that make those of us who remember punch cards feel very old
However, silicon is reaching the limits of not just its technology but the very laws of physics. Chip components have become so small that quantum effects, among other problems, are beginning to crop up, to the point where the silicon chip is set to suffer from the inevitable law of diminishing returns.
To overcome this, Diamond Quanta is working on swapping out silicon for diamond. That may seem like replacing plastic in your house with solid gold, but there's method in this seeming madness – as well as the promise of not only more advanced computers, but ones that work more efficiently and can even operate in high-temperature environments that make modern chips very unhappy.
We asked Adam Khan to explain it to us.
Before we get started, could you tell me a little about yourself and your company?
I'm Adam Khan, founder and CEO. I've had a little over 15 years in the field of lab-grown diamond technology. This is actually my second diamond semiconductor startup. The first was Akhan Semiconductor, which focused on thin-film nanocrystalline diamond.
As far as my background: I hold undergraduate degrees in physics and electrical engineering from the University of Illinois, Chicago, and did graduate work at Stanford University's Nano Fabrication Facility, focusing on micro-physicals. My previous company developed about 36 issued US patents primarily focused on diamond optics, mechanical coatings, and semiconductor devices.
Last year, in October 2023, I started exploring new methods in diamond technology, particularly in quantum applications and semiconductor materials. I identified and addressed a fundamental issue related to doping in diamond semiconductors, which typically degrades performance as more dopants are added. By focusing on charge transport and co-doping methods, we've achieved significant breakthroughs. We've begun releasing white papers and engaging with customers for validation of our technology.
So we're talking about a diamond semiconductor. Now, we know what a semiconductor is, but what's a diamond semiconductor? How does it operate?
We see this as the third wave of semiconductors. The first was germanium in the late 1940s, which transitioned from vacuum-based systems to transistors. Germanium had heating issues, which led to the adoption of silicon. Silicon revolutionized the industry but now faces limits due to heat and miniaturization as defined by Moore's Law.
Diamond, being an extreme material, offers unparalleled heat dissipation and fast electron movement. This is not natural diamond but lab-grown diamond made from methane precursor materials. It provides a path to continue silicon's legacy with vastly improved heat and performance capabilities.
What gives diamond this ability for heat dissipation? Is it the carbon in it, the crystalline nature, or something else?
The formal term is thermal conductivity, which essentially refers to heat transfer – how heat moves from one medium to another. Diamond's remarkable ability stems from its structure. The atoms in diamond are bonded very tightly together in a covalent structure, which is the strongest type of bond we know.
Because the atoms are so tightly packed, vibrations within the crystal structure, called phonons, can dissipate heat extremely efficiently. Diamond’s thermal conductivity is about 20 times better than silicon, making it ideal for high-heat applications.
And you said this idea has been around for about 20 years?
Yes, lab-grown diamonds date back to just after World War II, with the first systems created by General Electric. These used a high-pressure, high-temperature anvil. Later, chemical vapor deposition (CVD) techniques emerged, allowing diamond to be grown from gas precursors.
The process gained momentum in the early 2000s, leading to the ability to grow diamond in large wafers. Behind me, for example, is a 12-inch diamond wafer – the same size as silicon wafers. While we’ve mastered rendering diamond material for gem use, enabling it for semiconductor applications has been the challenge. Diamond is inherently insulating, so the difficulty lies in adding dopants to make it conductive without degrading the material or turning it into graphite.
What have been the obstacles to making this a practical technology?
The main challenge has been enabling charge transport within diamond. To be a successful semiconductor, diamond must outperform silicon and other materials like silicon carbide or gallium nitride. While diamond's heat dissipation is widely recognized, achieving better charge transport has been the bottleneck.
Our focus has been on doping – adding foreign atoms to the diamond structure to improve conductivity – without collapsing the diamond’s structure into graphite. Despite this challenge, diamond’s properties, like high power conductance, fast switching speeds, and superior thermal management, make it the ultimate wide-band-gap semiconductor.
Outside of heat conduction, how do diamond semiconductors perform compared to traditional technologies?
Diamond outperforms silicon and other semiconductors across multiple parameters, not just heat dissipation. It can handle the highest frequencies, highest power conductance, and fastest switching speeds. The key has been developing processes to add dopants without degrading these properties.
Currently, we’re implementing this in power device structures for applications like high-temperature automotive and data centers. Diamond’s ability to operate at over 600 °C (1,112 °F) without performance degradation is a game-changer, especially in environments where cooling systems are a significant burden, such as electric vehicles.
Do you see wider consumer applications for this technology? Could it help us overcome the limits of Moore's Law?
Yes, absolutely. Diamond-based chips could eventually be used in high-performance GPUs and logic applications. However, the immediate focus is on power semiconductors to mature the technology. In electric vehicles, for example, diamond can replace heavy cooling systems, reducing vehicle weight and increasing range.
Over the next five to 10 years, we see diamond entering broader applications, including high-temperature data centers, aerospace, and eventually consumer electronics.
Let’s talk about quantum computing. How does diamond fit into that field?
Diamond plays a key role in quantum computing due to its unique structure, specifically nitrogen vacancy (NV) centers. When nitrogen is added to diamond, it creates a pairing with vacancies (missing carbon atoms) that can form quantum bits or qubits. These qubits exhibit long coherence times, meaning they can maintain their quantum state for extended periods.
Diamond enables faster charge propagation and better qubit coherence compared to other materials. Around 40% of current quantum systems use diamond as a platform. Our co-doping approach further enhances this, allowing for more qubits without degrading performance. This positions diamond as a critical material for advancing quantum computing.
And has the cost of lab-grown diamond come down enough to make it viable?
Yes, dramatically. Thanks to advancements in lab-grown diamond production, costs are now comparable to silicon carbide and gallium nitride. While diamond traditionally evokes images of expensive gems, this is industrial-grade diamond optimized for technology. For example, the wafer you see behind me is far more cost-effective than mined diamond.
Finally, where do you see this technology in 10 years?
In 10 years, we envision diamond being as ubiquitous as silicon is today. It will likely start with high-performance applications – data centers, automotive, and aerospace – but over time, it will penetrate consumer electronics and computing systems. Diamond’s superior properties make it inevitable as the next wave of semiconductor technology.
