No, it's just one particular method of creating entangled pairs, e.g. there are integrated semiconductor devices that can be used to generate them using other physical effects (but AFAIK SPDC is what most people use in practical situations)
Interesting, do you have any search terms I could use to google for the semiconductor devices (I’ll try myself, but if you have a jumping off point that would be helpful).
Sure, one example that I'm familiar with is frequency entangled photons produced by parametric scattering of exciton-polaritons (it's scattering of quasiparticles in a quantum well which are strongly coupled to a photon field). Although, I actually can't recall if I've seen a convincing experimental demonstration of this.
I have seen a bunch of experimental results which demonstrated entanglement using integrated silicon waveguides, where there are two waveguides that overlap in an effective "beam splitter" section then separate again (this is analogous to how you can get entanglement from an Hong-Ou-Mandel setup, which is two (EDIT: identical photons) incident on a 50/50 beam splitter which produces so-called "path entangled" photons).
Here's a recent short review paper which goes over some additional semiconductor devices which can produce entangled photon pairs[1].
