Organic light-emitting diode displays with silicon and semiconducting oxide thin-film transistors
An electronic device may include a display having an array of display pixels on a substrate. The display pixels may be organic light-emitting diode display pixels or display pixels in a liquid crystal display. In an organic light-emitting diode display, hybrid thin-film transistor structures may be formed that include semiconducting oxide thin-film transistors, silicon thin-film transistors, and capacitor structures. The capacitor structures may overlap the semiconducting oxide thin-film transistors. The silicon transistors may be configured in a top gate arrangement. The oxide transistors may be configured in a top gate or a bottom gate arrangement. In one embodiment, source-drain contacts for the silicon and oxide transistors may be formed simultaneously. In another embodiment, the silicon and oxide thin-film transistor structures may be formed using at least three metal routing layers.
1. Display circuitry, comprising:
an organic light-emitting diode having an anode layer and a cathode layer;
a silicon thin-film transistor that includes a gate conductor and active silicon, wherein the silicon thin-film transistor is coupled to the organic light-emitting diode;
a top gate semiconducting oxide thin-film transistor that is coupled to the silicon thin-film transistor, that includes a gate conductor formed in a given metal layer, and that includes a semiconducting oxide layer, wherein the gate conductor of the silicon thin-film transistor is formed under the semiconducting oxide layer;
a first capacitor that is coupled to the silicon thin-film transistor and that includes an electrode formed in the given metal layer in which the gate conductor of the top gate semiconducting oxide thin-film transistor is formed, wherein the electrode is formed directly above another semiconductor oxide layer;
a second capacitor that is coupled to the silicon thin-film transistor and that includes a first electrode that is formed in the same layer as the active silicon and a second electrode that is formed in the same layer as the gate conductor of the top gate silicon thin-film transistor, wherein the second capacitor is formed directly underneath the top gate semiconducting oxide thin-film transistor to reduce area; and
an additional conductive layer that is formed in the same layer as the active silicon and that is coupled to a ground power supply line but not coupled to the anode layer of the organic light-emitting diode, wherein the additional conductive layer does not directly contact the active silicon.
2. The display circuitry defined in claim 1 , wherein the silicon thin-film transistor includes source-drain contacts formed as part of the given metal layer.
3. The display circuitry of claim 1 , wherein the silicon thin-film transistor has a source terminal coupled to the anode layer of the organic light-emitting diode.
4. The display circuitry of claim 1 , wherein the additional conductive layer is formed entirely below the top gate semiconducting oxide thin-film transistor.