Photoemission of Electrons fromn-Type Degenerate Silicon into Silicon Dioxide

Photoemission of electrons from both the conduction and valence bands of $n$-type strongly degenerate silicon (${10}^{26}$ electrons/${\mathrm{m}}^3$) into thermally grown silicon dioxide layers has been observed. The threshold energies have been determined for the two processes and are used to obtain the following information about energies at the silicon-silicon dioxide interface. The energy difference between the conduction-band edge in the silicon and that in the oxide is ∼3.29 eV. The energy difference between the valence-band edge in the silicon and the conduction-band edge in the oxide is ∼4.22 eV. The difference between these values is less than the optical band gap usually attributed to lightly doped silicon.