content: Any physicist would tell you that Moore's law is not a law of physics but more like  a law of marketing. Imagine any given technology is a ladder. Moore's law acts as a recipe to tell you how to space the individual steps in that ladder in order to maximize your profit, it does not tell anything about the technology itself.  Physically we have built a transistor made of single atom, naturally each such transistor needs thousand other atoms to support it, so we can't have a fabric made of single atom transistors stacked next to each other. This introduces a hard limit to Moore's law. Most likely 5nm will be the last technology level in that regard. From then on it will be impractical to make the transistors any smaller.  This does not mean that marketing or engineering research would stop. We still have areas that are woefully unexplored and will likely remain so for as long as the current technology remains profitable. In other words nobody is going to spend money on these unless they absolutely have to.  But as we near the end of planar silicon technology we will start to see. --  3D chip architectures -  Our current chips are planar i.e. flat. We can increase transistor density by stacking layers on top of each other. Cooling is a big problem though, if we can't cool it it won't work.    -- Alternative substrates - there are substrates which are faster and can take more heat than silicon. Nobody is using them because they are more expensive. Only microwave and radar people are using them in the moment. Silicon Carbide or Silicon on Sapphire -- Exotic stuff.    -- Specialized cores -- Today we only have general purpose computing cores on our processors. General purpose means it can do everything but rather slowly. Specialized application cores can be substantially faster for specific types of tasks. For example Vector Cores  or Stream Cores -- Architecture improvements -- We are still using the antiquated Von Neumann architecture only because this is what Intel makes. In fact there are better architectures like the Harvard Architecture which is a massive improvement over Von Neumann both performance and security wise.  Also we have things like the Inmos Transputer which solved the parallel computing and Von Neumann bottleneck back in '85!! Unfortunately they couldn't compete with Intel because Intel was American and Inmos was British, so just like the jet engine and the hovercraft the technology was abandoned to the yanks. Today the transputer style chips are only used in space applications because of their extreme reliability, the Philae lander for example has 2 onboard. If you are interested watch Iann Barron who invented it and there are efforts to revive his work with current technology.  -- Optics On Chip -- This could be a very big one. It is just starting to take off in the telecom field. It could significantly revolutionize things if applied to memory bus or system bus.