Analysis Of Preparation And Work Characteristics Of Zinc Oxide Thin Film Transistor Of Vertical Structure

Thin film transistor is the core component of driving circuit of active matrix organic light emitting diode(AMOLED) and thin film transistor liquid crystal displays(TFTLCD), the oxide TFT sprung up with advantages in mobility in charge carriers, uniformity and stability, that is the one of the most powerful competitors in pulling OLED forward. Therefore, there is great significance in the research of new oxide TFT.With the RF magnetron sputtering, make mutual reaction between zinc target with the purity of 99.99% and oxygen with the purity of 99.99%, zinc oxide film formed on the surface of quartz glass.With the help of scanning electron microscope(SEM) and X-ray diffraction(XRD) to analysis zinc oxide films with different substrate temperature、sedimentary time, then determine a set of procedure parameters to make the axial C orientation and the surface well.Ag/Zn O/Al diode ultraviolet detectors are made by OLED multi-function coating system, metal aluminium electrode and silver electrode are made by magnetic control DC sputtering, zinc oxide semiconductor layer is made by RF magnetron sputtering. The dark current of ultraviolet detectors、light optical and capacitance-voltage under light beam with 365 nm wavelength are tested. After analysis the data, the I-V curve of schottky barrier get effective height of 0.53 e V, ideal factor of 12.6. Capacitance-voltage curve get schottky barrier of 0.6 e V, different theories get different schottky barrier height with slight differences, which is acceptable, calculated schottky barrier height confirm with that Ag and Zn O semiconductor layer has formed schottky contact. The ultraviolet detectors depletion layer thickness is with order of nano magnitude, the concentration of carriers is 3.13 x 1016 cm-3. Ultraviolet detectors with bias valtage of 2 V, 3 V could creat current light with orders of MA magnitude, the performance is better than the other detectors.Researches are made about different sedimentary time, zinc oxide thin film transistor of vertical structure with substrate temperature of different substrates. The results show that, thin film transistor with well perfprmance at static i-v characteristics will be got on quartz glass panels with deposition time of 120 min, substrate is not heated small bias voltage(< 1.0 V) is appliled on Aluminum film, in which the drain-source voltage, for 3 V drain-source current can achieve m A orders of magnitude current, threshold Vth is about 1.35 V, much smaller than the present study top and bottom gate structure, leakage source current is larger by one to two orders of magnitude. Use Fowler-Nordheim tunneling injection model to analysis the carriers, the preparation of zinc oxide thin film transistor is through via election from source Ag film tunneling into Zn O semiconductor layer by barrier formed while getting through Ag and Zn O film, the tunneling current is controlled by source voltage.