In this paper, we review the basic components of superconducting quantum computers. We mainly focus on the packaging and wiring technologies required to realize large-scalable superconducting quantum computers.

We study individual carrier traps in a GaAs/AlxGa1-xAs heterostructure by observing random telegraph signals. A narrow channel, which is formed in a split gate device, is shifted by independently controlling the voltage applied to each part of the split gate. RTSs can be observed only when the traps are close to the channel and the energy levels of the traps are within a few kBT of the Fermi level. This type of measurement reveals the locations and the energy distributions of the traps. We also discuss the situation in which two trap levels are at the Fermi level simultaneously. In this condition the two RTSs do not occur at the same time, but they do interact with each other. This implies that there is an electrostatic interaction between the two trappings.

In this paper, we briefly review the concept of superconducting quantum computers and discuss their hardware architecture. We also describe the necessary technologies for the development of a medium-scale quantum computer with more than tens of thousands of quantum bits.