3D transistors are made thanks to Intel's revolutionary technology called Tri-Gate which, thanks to a 22nm technological process, keeps us abreast of Moore's law.
Topic to be studied both on Moore's law side (Will chip development follow Moore's law?) And on the scientific side with the discovery of 3D crystals.

Mark Bohr, who has been with Intel for some time, explains everything: here is a small excerpt from the interview, while you can find the complete interview (complete with video) on EOS.

Hi, I'm Mark Bohr and I've been here in Intel for some time! Many know Intel as a microprocessor builder but most of us know that each MCU is made up of millions or
even billions of microscopic electrical components: transistors! As time goes by, transistors get smaller and smaller according to Moore's Law whereby computers and all communication devices get smaller, "smart" and more efficient! Taking into account Moore's Law is not an easy thing ...

Read the rest and watch the video interview on Open Source Electronics