Very fast digital gates
Emitter coupled logic is that you want, like the https://www.digikey.co.uk/product-detail/en/MC10EP08DTG/MC10EP08DTGOS-ND/920778?curr=gbp&amp;WT.z_cid=ref_octopart_dkc_buynow&amp;site=us

Why do you need it to go that fast?

If you want your circuit to actually go at GHz speeds, you'll need to take a lot of things into account other than just the chip.