Transparent transistors based on semiconducting oxides

The synthesis and properties of oxide-based thin film transistors (TFTs) is reported using pulsed laser deposition. The field effect transistors use ZnO as the channel material. Low leakage current density is achieved with amorphous (CeTb)MgAl₁₁O₁₉ (CTMA) serving as the gate oxide, whose dielectric strength is measured to be > 5MV/cm for structures fabricated on Indium Tin oxide (ITO) substrates. Capacitance-voltage properties show that n-type active layers are realized with undoped ZnO. Charge densities in undoped ZnO are measured to be 10¹⁸ to 10¹⁹ / cm³ using Hall measurement and CV plots. Current-voltage measurements for TFT operation are reported. Channel materials on patterned substrates show high conductance and modulation of channel conductance. C-V measurements with MOS structure using doped ZnO and Zn_xMg_1-xO will also be described. The properties of depletion mode TFTs fabricated with doped and undoped oxide channel will be discussed in detail.