In₂O₃:Er films have been synthesized on silicon substrates by RF magnetron sputter deposition. The solid solution ((In_1-xEr_x)₂O₃) is formed here. The 1.534 mkm erbium electroluminescence is observed by the forward current through the investigated hetero-structure: substrate-n-Si\In₂O₃:Er-film\ITO-contact. The Er excitation model by the electron-hole recombination is proposed. The model consist of the electrons at the indium oxide conduction band. And the hole current is through the channel at the middle of the In₂O₃:Er band gap. The hole channel is formed by the defect state density spreading from the valence band edge into the band gap. Therefore the electron-hole recombination energy is lower then the indium oxide band gap and equals to the 1.56 eV. Then the electron-hole recombination excites in resonance the third excited state of Er^{3+ 4}I_9/2 (1.53 эВ). Then the non-radiative relaxation to the first excited state ⁴I_13/2 (0.81 эВ) occurs. And finally the 1.534 mkm radiative emission into ground state ⁴I_15/2 occurs.