Re:What's Different About Next-Gen Transistors
by metadat on Friday October 21, 2022 @10:15PM
(#33295072)
Wow, that's a remarkably informative image, thank you @ThrowawayR2.
Re:What's Different About Next-Gen Transistors
by tux1968 on Saturday October 22, 2022 @01:51AM
(#33295917)
Steps 7, and especially 8, seem like magic without a good explanation of how they're possible.
Re:What's Different About Next-Gen Transistors
by bippingchip on Saturday October 22, 2022 @02:26AM
(#33296025)
That’s because they skip quite a few steps. You would first deposit a photosensitive layer, then expose it wit a pattern of light, which will allow you to selectively open up the parts you want to toch next.
For step 7 for example, you create a masking layer that way, after which you etch away only the exposed parts where source and drain contacts will end up.
For step 8, you do something similar. The openings you’ve etched in step 8 will allow only to dope the contacts, but you need to mask the nmos and pmos separately, otherwise you get the same doping in both transistors.
A lot of the ‘magic’ to make this work is in the materials and chemistry: you need selectivity: etching that only interacts with the exposed parts. In highly scaled finger nodes, the material combinations are very complex as you sometimes want 2, or 3 different material combinations to interact in the way you want, reliably, at nanometer scale.
The Wikipedia article on CMOS has a very nice illustration of the basic steps of this process: https://en.wikipedia.org/wiki/CMOS#/media/File:CMOS_fabricat... Current processes are much more complex than even that.