Investigation of growth characteristics, compositions, and properties of atomic layer deposited amorphous Zn-doped Ga2O3 films

Diethylzinc and H2O were used as the precursors for the thermal atomic layer deposition (TH-ALD) of ZnO deposition while the trimethylgallium and O-2 plasma were used as a reactant for the plasma-enhanced atomic layer deposition (PE-ALD) of Ga2O3, respectively. The Zn-doped Ga2O3 (ZGO) films were fabricated by a combination of PE-ALD of Ga2O3 and TH-ALD of ZnO at a low temperature of 200 degrees C. The results show that asdeposited ZGO films were amorphous while ZnO with a crystalline structure. XPS results indicate that the Zn content in ZGO films increased from 9.70 to 24.65 at.% with the cycle ration of Ga2O3 with respect to ZnO decreasing from 7:1 to 3:1 while the oxygen vacancy increased from 27.65% to 37.93%. The rise in Zn doping contents is also accompanied by significant variations in the morphological, electrical, and optical properties of the ZGO films, including a decrease of film density and resistivity, an increase of RMS roughness, a strong transmittance in the ultraviolet-visible (UV-vis) area, and a widening of the band gap from 4.64 to 5.25 eV. These findings help deposit ZGO films with desired structure and properties for electronic device applications.