Last night while channel surfing I came across Men in Black III, and was dropped right into the scene where a 1969 Tommy Lee Jones was placing Will Smith into the Neuralizer pictured on the left. For those not familiar with the original 1997 MiB franchise a Neuralizer is a cigar-sized plot device for washing peoples memories of an alien encounter that is normally carried inside their jacket pocket. The writers were clearly poking fun at miniaturization and how much humanity has come to take it for granted.

Those of us who grew up in the 1960s and 70s lived through the miniaturization wave as the Japanese led the industry by shrinking radios and televisions from cabinet sized living room appliances to handheld devices. One year for Father’s Day in the late 70s we bought my dad a portable black and white TV with a radio that ran on batteries so he could watch it on the boat in the evenings. It was roughly the size of three laptops stacked on top of one another. It may sound corny now, but it was amazing back then. Today we watch theater quality movies in color, on a much larger screen from a device that drops into our pocket and don’t think twice about it. We’ve grown accustom to technology improving at a rapid rate, and it’s now expected, but what happens when that rate is no longer sustainable?

Last year the industry began etching chips with a new seven nanometer process, which is equivalent to Intel’s 10nm process. Apple’s A12 Bionic chip that powers their XR and XS series iPhones is one of the first using this new 7nm process. This chip contains 6,900 million transistors and is arguably one of the most advanced devices every produced by mankind. By contrasts, my first computer in 1983 was a TRS-80 Model III powered by the Zilog Z80 processor. The Z80 used a 4,000nm process and only contained 8,500 transistors. So in 35 years we’ve reduced the process size by three orders of magnitude resulting in a transistor density improvement of six orders of magnitude, wow! How do we top that, and where are we in the grand scheme of the physics of miniaturization?

In a 1965 paper by Gordon Moore, then founder of Fairchild Semiconductor and later CEO of Intel, Gordon stated that the density of integrated circuits would double every year, now known as Moore’s Law. From 1970 through 2014 this “law” had essentially proved true. Before Intel’s current 10nm geometry their prior generation was 14nm and that was achieved in 2014 so it’s taken them five years to accomplish 10nm. Not exactly Moore’s law, but that’s the tip of the iceberg. As the industry goes from 14nm to 7nm/10nm physics is once again throwing up a roadblock, this hasn’t been the first one, but it could be the last one. Chips are made using Silicon, and Silicon atoms have a diameter of about 0.2 nanometers. So at a seven nanometers node size, we’re talking 35 or so silicon atoms, which isn’t a very large number. It turns out that below seven nanometers, as we have fewer and fewer silicon atoms to manage electron flows, things get dicey. Chips begin to experience quantum effects, most notably those pesky electrons, which are about a millionth of a nanometer in size, begin to exhibit something called quantum tunneling. This means that they no longer behave like they are supposed to and they move between devices etched into the silicon with a sort of reckless disregard for the “normal” rules of physics. This has been known though for some time.

Back in 2016 a team at Lawrence Berkley National Labs demonstrated a one nanometer transistor device, but that leveraged Carbon nanotubes to manage electron flow and stave off the quantum tunneling effect. For those not familiar with Carbon nanotubes think teeny tiny diamond straws where the wall of the straw is one atom thick. While using Carbon nanotubes to solve the problem is ingenious, it doesn’t fit into how we make chips today as you can’t etch a Carbon nanotube using conventional chip fabrication processes. So while it’s a solution to the problem it’s one that can’t easily be utilized. So we may be working at 7nm for some time to come. This only means that one aspect of miniaturization has ground to a halt. When I’ve used the term chip above to represent an integrated circuit the more precise term is actually a “die.”

Until recently it was common practice to place a single “die” inside a package. A package is what most of us think of as the chip as it has a bunch of metal pins coming out of the bottom or sides. In recent years the industry has developed new techniques that allow us to layer multiple dies onto one another within the same physical package enabling the creation of very complex chips. This is similar to a seven-layer cake where different types of cake can be in each layer and the icing can be used to convey flavors across the cake layers. This means that a chip can contain several and eventually many dies, or layers. A recent example of this is Xilinx’s new Versal chip line.

Within the Versal chip package there are multiple dies that contain two different pairs of ARM CPU cores, hundreds of Artificial Intelligence (AI) engines, thousands of Digital Signal Processors (DSP), a huge Field Programmable Gate Array (FPGA) area, several classes of memory, and multiple programmable memory, PCIe and Ethernet controllers. The Versal platform is a flexible toolbox of computational power, with the ARM cores handling traditional CPU and real-time processing tasks. The AI cores churn through new machine learning workloads while the DSPs are leveraged for advanced signal processing, think 5G, and the FPGA can be used as the versatile computational glue to pull all these complex engines together. Finally, we have the memory, PCIe and Ethernet controllers to interface with the real world. So while Intel and AMD focus on scaling the number CPU cores on the chip and NVidia works to improve Graphical Processing Unit (GPU) density Xilinx’s is the first to go all-in on chip-level workload integration. This is the key to accelerating the data center going forward.

So until we solve the quantum tunneling problem, with new fabrication techniques, we can utilize advances in integration as shown above to move the industry forward.