  Single-electron effects have been widely investigated as a typical physical
phenomenon in nanoelectronics. The single-electron effect caused by trap sites
has been observed in many devices. In general, traps are randomly distributed
and not controllable; therefore, different current--voltage characteristics are
observed through traps even in silicon transistors having the same device
parameters (e.g., gate length). This allows us to use single-electron effects
as fingerprints of chips. In this study, we analyze the single-electron effect
of traps in conventional silicon transistors and show the possibility of their
use as fingerprints of chips through image recognition algorithms. Resonant
tunneling parts in the Coulomb diagram can also be used to characterize each
device. These results show that single-electron effects can provide a quantum
version of a physically unclonable function (quantum-PUF).
