Comment by measurablefunc
1 day ago
Density is mass per volume so how are you comparing it to a planar transistor? Your units don't even match.
1 day ago
Density is mass per volume so how are you comparing it to a planar transistor? Your units don't even match.
All "density" means is that it's a quotient; I use spectral densities daily and that's "count per Hertz" which weirdly enough works out in normal units to be seconds.
Not all densities is mass per volume. eg. population density.
It's a physical quantity per some unit of spatial measurement so the units still don't match up b/c in one case the transistors are stacked per volume & in the other case per area.
> Historically, "node" sizes (like 28nm or 7nm) directly correlated to the physical length of a transistor's gate. Today, names like 3nm or 2nm reflect a marketing generation. The actual transistors are significantly larger than these nanometer labels, meaning density varies between companies
> Research organizations like IEEE have proposed new metrics, such as transistors per cubic millimeter (MTr/mm^3), to accurately map future 3D scaling. However, commercial chip foundries resist this change because it would make it harder to calculate commercial yields and thermal density limits using standard industry formulas.
https://share.google/aimode/Z5BqUjlZWFNphm6Z6
The comparison is good. Humans are also stacked in volumes and we still measure population density over a surface because the third dimension is less significant in this context.
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> It's a physical quantity per some unit of spatial measurement so the units still don't match up b/c in one case the transistors are stacked per volume & in the other case per area.
"Planar" and "3D" in this context refers to the shape of the transistors themselves. In a planar transistor the functional structure is spread out in the area, like this: https://en.wikipedia.org/wiki/File:MOSFET_functioning_body.s... while 3D transistors spread into the volume: https://en.wikipedia.org/wiki/Multigate_device#/media/File:D...
However the active devices are still just one layer. This isn't like 3D NAND where you actually have transistors on top of each other. So the comparison only considers the area for both kinds of transistors.
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Population density isn’t planar, eg, why cities are denser than towns: their centers are more than 2D.
Population density is literally measured over a planar metric: people/km^2
You are suggesting it's measured over a cube volume?
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density is quantity per unit measure.
mass per volume is one example.
Density is this reply.
https://en.wikipedia.org/wiki/Transistor_count#Transistor_de...