The first idea for a qubit based upon Si arises from the suggestion of Kane to use a 31P dopant in isotopically pure 28Si (silicon, like many materials, has different isotopes that have different numbers of neutrons) (Kane in Nature 393:133, 1998). This would enable a silicon platform for quantum technology that would easily integrate with normal silicon microchips. This is an intriguing approach to continue the dominance of silicon in the nanoelectronics, and now the quantum, world. Indeed, some integration of silicon quantum circuits has already appeared (Holman et al. in NPJ Quantum Inform. 7:137, 2020). Since the work of Kane, many other qubit concepts, that have their root in the silicon world, have arisen. As a result, other integration platforms have been suggested (Thomas et al. in Mater. Quantum Techn. 2, 2022;Michielis et al. in J. Phys. D: Appl. Phys. 56, 2023;). These different approaches have naturally led to different suggestions for the implementation of the basic qubit.