Moore's Law no more?

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In the interests of self-education, you might like to take a Friday look at a longish article up on El Reg this week by Rupert Goodwins, looking at the minutae of how silicon chips are made, down to the nanometre level, and how Gordon Moore's famous 'law', wherein chip density doubles every two years, is starting to fail as chip makers come up increasingly hard against the laws of physics. It had to happen. But it's a fascinating read over a beverage. Plus, you have to wonder, aren't today's chips (in phones, tablets, PCs) now small and fast enough? Do we need to push the boundaries even further?

From The Register article:

Modern chip manufacturers specify their processes in nanometres, which for a long time was a convenient way to describe the length of a particular feature in the standard metal-oxide semiconductor field effect transistor (MOSFET) at the heart of integrated logic. These planar devices have a simple layered construction. A switching area, called the gate, lies underneath a switched area called the source-drain channel, and a voltage on the first switches current in the second. The feature size – say, 22nm – referred to the smallest gate length, hence the number of transistors that could fit in a particular area.

Around the mid 1990s, though, the physics started to get unhelpful. MOSFETs are configured in complementary pairs (CMOS) in logic chips, where one turns off and the other on to make a logic one, and vice-versa for a zero. This means they only use power when switching, not when they're holding a state, meaning many millions of transistors could be put on a chip without it burning up. But at a certain point, as transistors get smaller they become less good at isolating voltage and leakage current goes up, much as many materials become transparent when they're made thin enough. Noise too becomes a problem, as does gate delay time – the speed at which a voltage on the gate switches the channel, thus how fast the transistor operates – and while various engineering fixes like high-K dielectrics – thinner insulation with better performance – prolonged the life of planar transistors into the upper 20nm ranges, new non-2D structures were needed.

And so on. You thought you knew how chips were made in 2021? Think again, it's a wild ride and almost magical in terms of the density of components.

Do read the whole article, but from the conclusion:

It's not just that there's no clear leader for continuing Moore's Law once CMOS runs out, it's that there's not even a pack of hopefuls. Moore's Law has induced more than half a century of intensive investment in making CMOS better, the end results of which are production lines finely tuned to creating billion-transistor chips at an atomic scale, with an armoury of tools and expertise around them. No technology still in the lab is going to leapfrog that by 2025.

New developments will continue, especially in non-general purpose computing such as AI and numeric analysis as architectures are fine-tuned to particular tasks. But on every front, the economics and physics of Moore's Law no longer apply. It's been a wild ride, as significant as the Industrial Revolution, and there's lots to sort out for generations to come. But the great engine that set us on the new course is falling silent, and the time is coming to say – no Moore.

Amazing stuff. Most things in life we could recreate fairly quickly from first principles, in terms of tech. A sewage system. A gas boiler. An oven. Even a generator. But if someone asked you, on a desert island, to recreate a silicon chip then you'd be very quickly back to breadboards and the most basic and visible resistors and transistors. If the chip industry were ever to disappear then we'd all be in a lot of trouble(!)

Source / Credit: The Register