Not really. Our substrate today is silicon (really n-type silicon). We build a city on top of that substrate. Modern semiconductors have become way more heterogenous in recent years. Our gate insulators are not silicon dioxides anymore but high-k dielectrics such as hafnium oxide. And even interconnects now have different compositions, such as cobalt and copper.
But the substrate is still holding us back, and one reason for that is creating high-quality single crystal wafers for silicon that are way more manageable.
The solution for a long time has been to use direct bandgap semiconductors such as GaN, AlN, and so on. Silicon is an indirect bandgap semiconductor, meaning its conduction and valence bands are not aligned in momentum space. As a result, electrons hopping between these bands pay a thermal penalty. GaN and AlN don't have that problem, and we now have a plethora of crystals (especially complex oxides) that are all direct, and we have an entire library of bandgaps to choose from.
The problem is that we cannot easily make wafers from these direct bandgap systems. At least yet to be on any commercial scale. Honestly, rather than flushing billions of dollars down the toilet for Zuck's vanity projects - we should have spent money to scale up Czochralski's growth[1] for a ton of crystal families. But, as we are reaching the limits for reticule sizes and we move to chiplet architectures, maybe smaller wafers will work too?
