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. Organic light-emitting diode display pixels may have combinations of oxide and silicon transistors. In a liquid crystal display, display driver circuitry may include silicon thin-film transistor circuitry and display pixels may be based on oxide thin-film transistors. A single layer or two different layers of gate metal may be used in forming silicon transistor gates and oxide transistor gates. A silicon transistor may have a gate that overlaps a floating gate structure.
1. An electronic device comprising a display with a display pixel, wherein the display pixel comprises:
a light-emitting diode;
a plurality of transistors that is configured to control an amount of light emitted by the light-emitting diode, wherein the plurality of transistors includes a semiconducting oxide thin-film transistor having a first gate and a silicon thin-film transistor having a second gate;
a capacitor coupled to at least one of the plurality of transistors, wherein the capacitor has first and second electrode layers;
a layer of metal that is patterned to form the second gate and the first electrode layer;
a first dielectric layer formed over the layer of metal; and
a second dielectric layer formed over the first dielectric layer.
2. The electronic device defined in claim 1 , wherein the silicon thin-film transistor has a polysilicon channel and is coupled to the capacitor.
3. The electronic device defined in claim 1 , wherein the first gate is formed from another portion of the layer of metal.
4. The electronic device defined in claim 1 , wherein the semiconducting oxide thin-film transistor has a semiconducting oxide channel region and is coupled to the light-emitting diode.
5. The electronic device defined in claim 1 , wherein the capacitor is a storage capacitor configured to store data associated with a frame.
6. The electronic device defined in claim 1 , wherein an additional layer of metal is interposed between the first and second dielectric layers.
7. The electronic device defined in claim 1 , wherein the first dielectric layer is silicon oxide.
8. The electronic device defined in claim 1 , wherein the first dielectric layer is silicon nitride.
9. An electronic device comprising a display with a display pixel, wherein the display pixel comprises:
a light-emitting diode;
a plurality of transistors that is configured to control an amount of light emitted by the light-emitting diode, wherein the plurality of transistors includes a semiconducting oxide thin-film transistor having a first gate and a silicon thin-film transistor having a second gate;
a capacitor coupled to at least one of the plurality of transistors, wherein the capacitor has first and second electrode layers; and
a layer of metal that is patterned to form the second gate and the first electrode layer, wherein the semiconducting oxide thin-film transistor comprises a layer of semiconducting oxide and wherein the first gate and the layer of semiconducting oxide are overlapping.
10. The electronic device defined in claim 9 , wherein the first gate comprises molybdenum.
11. The electronic device defined in claim 9 , wherein the first gate comprises molybdenum and a metal that is different from molybdenum.
12. The electronic device defined in claim 9 , wherein the first gate comprises molybdenum and a refractory metal that is different from molybdenum.
13. The electronic device defined in claim 12 , wherein the refractory metal that is different from molybdenum comprises tungsten.
14. A display pixel comprising:
a light-emitting diode;
a plurality of transistors that is configured to control an amount of light emitted by the light-emitting diode, wherein the plurality of transistors includes a semiconducting oxide thin-film transistor having a first gate and a silicon thin-film transistor having a second gate;
a capacitor coupled to at least one of the plurality of transistors, wherein the capacitor has first and second electrode layers; and
a layer of metal that is patterned to form the second gate and the first electrode layer, wherein the semiconducting oxide thin-film transistor comprises a layer of semiconducting oxide and wherein the first gate and the layer of semiconducting oxide are overlapping.