This study alleviates the low operating temperature constraint of Si qubits.<br />
A qubit is a key element for quantum sensors, memories, and computers. Electron<br />
spin in Si is a promising qubit, as it allows both long coherence times and<br />
potential compatibility with current silicon technology. Si qubits have been<br />
implemented using gate-defined quantum dots or shallow impurities. However,<br />
operation of Si qubits has been restricted to milli-Kelvin temperatures, thus<br />
limiting the application of the quantum technology. In this study, we addressed<br />
a single deep impurity, having strong electron confinement of up to 0.3 eV,<br />
using single-electron tunnelling transport. We also achieved qubit operation at<br />
5-10 K through a spin-blockade effect based on the tunnelling transport via two<br />
impurities. The deep impurity was implemented by tunnel field-effect<br />
transistors (TFETs) instead of conventional FETs. This work heralds the age of<br />
high-temperature quantum technology on silicon platforms.