Fabrication of electronic circuit elements using unpatterned semiconductor layers

• US 6,683,333 B2
• Filed: 07/12/2001
• Issued: 01/27/2004
• Est. Priority Date: 07/14/2000
• Status: Expired due to Fees

• Current Assignee: E Ink
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Drzaic, Paul S., Danner, Guy M., Kazlas, Peter T., Hack, Michael G., Amundson, Karl R.
• Primary Examiner(s): Nhu, David
• Application Number:
  US09/904,109
• Publication Number:
  US 20020106847A1
• Time in Patent Office: 929 Days
• Field of Search: 257/192, 257/197, 257/213, 257/273, 257/350, 257/401, 257/557, 257/565, 257/901, 257/902, 257/903
• US Class Current: 257/197
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 28/60 Electrodes
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate

Abstract

A thin-film transistor array comprises at least first and second transistors. Each of the first and second transistors include a shared silicon layer, i.e., an active layer. The shared semiconductor layer extends continuously between the first and second transistors, and includes a concentration of dopant that increases a resistivity of the semiconductor layer and reduces a leakage current through the semiconductor layer while permitting functioning of the transistor array.

Claims

1. A thin-film transistor array comprising at least first and second transistors, each of the first and second transistors comprising:

a shared semiconductor layer extending continuously between the first and second transistors, and the semiconductor layer doped to increase a resistivity of the semiconductor layer and reduce a leakage current through the semiconductor layer while permitting functioning of the transistor array;

a source electrode adjacent to the semiconductor layer;

a drain electrode spaced from the source electrode and adjacent to the semiconductor layer; and

a gate electrode disposed adjacent to the semiconductor layer.

2. The thin-film transistor array of claim 1 wherein the semiconductor layer comprises unpatterned silicon.

3. The thin-film transistor array of claim 2 wherein the semiconductor layer has a thickness less than 40 nm, and the source electrode is in direct contact with the semiconductor layer.

4. The thin-film transistor array of claim 1 wherein the semiconductor layer comprises amorphous silicon.

5. The thin-film transistor array of claim 4 wherein the semiconductor layer further comprises dopant comprising p-type dopant.

6. The thin-film transistor array of claim 5 wherein the semiconductor layer further comprises dopant comprising boron.

7. The thin-film transistor array of claim 1 wherein the first transistor is a bottom gate transistor.

8. The thin-film transistor array of claim 1 wherein the first transistor is a top gate transistor.

9. The thin-film transistor array of claim 1, the first transistor further comprising a first pixel electrode of an electronic display, the first pixel electrode in communication with the source electrode of the first transistor, and the drain electrode of the first transistor is in communication with a first data line of the electronic display.

10. The thin-film transistor array of claim 9 wherein a distance between the first pixel electrode and the first data line is selected to provide an acceptable leakage current between the first pixel electrode and the first data line.

11. The thin-film transistor array of claim 9 wherein a distance between the first transistor and the second transistor is selected to provide an acceptable leakage current between the first data line and the second data line.

12. The thin-film transistor array of claim 11 wherein at least one of the first data line, the second data line, the first transistor and the first pixel electrode have a geometry selected to provide an acceptable leakage between the first data line and the second data line.

13. An electronic display comprising:

a display medium;

a first pixel electrode and a second pixel electrode provided adjacent to the display medium; and

a first thin-film transistor and a second thin-film transistor in respective electrical communication with the first pixel electrode and the second pixel electrode, and comprising a shared continuous semiconductor layer that provides channels for the first thin-film transistor and the second thin-film transistor, and the semiconductor layer doped to increase a resistivity of the semiconductor layer and reduce a leakage current through the semiconductor layer while permitting functioning of the first and second thin-film transistors.

14. The electronic display of claim 13 wherein the display medium is electrophoretic.

15. The electronic display of claim 14 wherein the electrophoretic medium comprises at least one type of particle and a suspending fluid.

16. The electronic display of claim 14 wherein the electrophoretic medium is encapsulated.

17. The electronic display of claim 13 further comprising a light blocking layer provided adjacent to the semiconductor layer.

18. The electronic display of claim 13 further comprising a first data line in communication with the first transistor and a second data line in communication with the second transistor, wherein a distance between the first transistor and the second transistor is selected to provide an acceptable leakage between the first data line and the second data line.

19. The electronic display of claim 18 wherein a distance between the first pixel electrode and the first data line is selected to provide an acceptable leakage between the first pixel electrode and the first data line.

20. The electronic display of claim 13 wherein the first transistor comprises a gate electrode, a source electrode and a drain electrode and the gate electrode and one of the source electrode and the drain electrode form a capacitor.