Metal oxide thin film transistor and a preparation method thereof

A preparation method of a Metal Oxide Thin Film Transistor (MOTFT), comprising the following steps in turn:

• Step a:
• a metal conductive layer is prepared and patterned as a gate on a substrate;
• Step b:
• a first insulating thin film is deposited as a gate insulating layer on the metal conductive layer;
• Step c:
• a metal oxide thin film is deposited and patterned as an active layer on the gate insulating layer;
• Step d:
• an electrically conductive organic thin film is deposited as a back channel etch protective layer on the active layer, wherein the thickness of the back channel etch protective layer is set as 1 to 50 nm;
• the organic conductive thin film is specifically formed by depositing an organic material including fullerene (C60), a fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), a carbon nano tube, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), or aluminium tris-hydroxyguinoline (Alq3);
• a film-foiniing method of the back channel etch protective layer is a spin coating method, or a vacuum thermal evaporation method, or silk screen printing or film forming using an ink-jet printing method;
• Step e:
• a metal layer is deposited on the back channel etch protective layer and then patterned as pattern of a source electrode and a drain electrode whereby the electrically conductive organic thin film between the source and drain electrodes is removed;
• and
• Step f:
• a second insulating thin film is deposited as a passivation layer on the source electrode and the drain electrode.