I want to build a low-bias current (\$\ll\$1 pA) amplifier with a MOSFET for the fun of it. However, after testing the gate-source leakage current of some 2N7002s I was shocked that they leak roughly 1 nA at 1 V at room temperature, so are pretty useless for this project.
I then found this article on unprotected and ESD-protected MOSFET from Nexperia which seems to confirm that the leakage at this order of magnitude is indeed normal for ESD-protected MOSFETs, whereas unprotected MOSFETs should leak negligible currents at low bias.
After looking around a bit I couldn't find other unprotected parts other than the one mentioned in that article (BSS138P). Can you recommend a strategy for finding them ? Google just brought me back to that article and countless other MOSFETs, which weren't actually unprotected.