Here is a really interesting microscope photograph and analysis of the insides of a TL084 op-amp: http://www.righto.com/2018/06/silicon-die-analysis-op-amp-with.html, link posted by marcelomd over at DIYSB. The author breaks down the structure of the various transistors and why they are shaped that way. The amount of engineering that goes into even a "simple" op-amp has always impressed me.
Of note re the recent discussion of the LM308 and its need for an external frequency compensation capacitor, you can see that the TL084's internal capacitors are the largest area on the chip, even though they are a very small value cap (because there's no high-dielectric material to work with).
Of note re the recent discussion of the LM308 and its need for an external frequency compensation capacitor, you can see that the TL084's internal capacitors are the largest area on the chip, even though they are a very small value cap (because there's no high-dielectric material to work with).