Using variable pressure for tuning the band structure and variable infrared light pulse intensity for tuning the number of Si‐related shallow donor metastable states, we have demonstrated that these states are effective mass‐like states linked to each of the conduction band &Ggr;,L, andXminimum. The evolution of their binding energies with their increasing density is shown to decrease and the Mott transition for the &Ggr;‐like states has been also observed.