Hello,
The circuit is a bandgap reference, very similar to the Banba reference (replace the BJT diodes with mosfets), the technology is a FinFET process, unfortunately I cannot say much more about the process. The idea behind the circuit is to use the subthreshold devices in a way that mimics the behaviour of the BJT.
I know that the OP Amp has a significant effect on the reference voltage, but one thing I noticed was that the voltage across the diodes had the most significant variation when subjected to process variations. Mismatch does not have much, if any, of an effect on my circuit, which is why I did not think it was the amplifier. The strong dependence on threshold voltage in subthreshold operation would dictate the variations of voltage across the diodes which is why I am trying to come up with a way to reduce that, either by sizing(which I have done, W*L is large), or by implementing some feedback.
Thanks!