FIELD EFFECT TRANSISTOR, DISPLAY ELEMENT, IMAGE DISPLAY DEVICE, AND SYSTEM

• US 20110128275A1
• Filed: 08/13/2009
• Published: 06/02/2011
• Est. Priority Date: 08/20/2008
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kondo, Hiroshi, Abe, Yukiko, Nakamura, Yuki, Ueda, Naoyuki, Sone, Yuji
• Application Number:
  US12/737,688
• Publication Number:
  US 20110128275A1
• Time in Patent Office: Days
• US Class Current: 345/212
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A field effect transistor includes a gate electrode to which a gate voltage is applied; a source electrode and a drain electrode for obtaining a current in response to the gate voltage; an active layer provided adjacent to the source electrode and the drain electrode and formed of an oxide semiconductor including magnesium and indium as major components; and a gate insulating layer provided between the gate electrode and the active layer.

Claims

1. A field effect transistor comprising:

a gate electrode to which a gate voltage is applied;

a source electrode and a drain electrode for obtaining a current in response to the gate voltage;

an active layer provided adjacent to the source electrode and the drain electrode and formed of an oxide semiconductor including magnesium and indium as major components; and

a gate insulating layer provided between the gate electrode and the active layer.

2. The field effect transistor as claimed in claim 1, wherein the oxide semiconductor has a volume resistivity of 10⁻

2 Ω

cm to 10⁹ Ω

cm.

3. The field effect transistor as claimed in claim 1, wherein the indium included in the oxide semiconductor is partly substituted by at least one of aluminum and gallium.

4. The field effect transistor as claimed in claim 1, wherein the magnesium included in the oxide semiconductor is partly substituted by at least one of calcium, strontium, and barium.

5. The field effect transistor as claimed in claim 1, wherein the oxide semiconductor has at least a part having a spinel structure or an olivine structure.

6. The field effect transistor as claimed in claim 1, wherein the oxide semiconductor has at least a part that is amorphous.

7. The field effect transistor as claimed in claim 1, wherein the oxygen included in the oxide semiconductor is partly substituted by at least one of nitrogen and fluorine.

8. A display element comprising:

a light control element whose light output is controlled according to a driving signal; and

a driver circuit including the field effect transistor as claimed in claim 1 and configured to drive the light control element.

9. The display element as claimed in claim 8, wherein the light control element includes an organic electroluminescent element.

10. The display element as claimed in claim 8, wherein the light control element includes a liquid crystal element.

11. An image display device for displaying an image according to image data, comprising:

a plurality of the display elements as claimed in claim 8 arranged in a matrix;

a plurality of wires configured to apply a gate voltage individually to each of the field effect transistors of the plurality of display elements; and

a display control device configured to individually control the gate voltage applied to each of the field effect transistors through the plurality of wires according to the image data.

12. A system comprising:

the image display device as claimed in claim 11; and

an image data forming device configured to form image data according to image information to be displayed and output the image data to the image display device.