Transistor including a deposited channel region having a doped portion

• US 7,564,055 B2
• Filed: 07/24/2007
• Issued: 07/21/2009
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Hoffman, Randy
• Primary Examiner(s): Tran; Minh-Loan T
• Assistant Examiner(s): Harriston; William
• Application Number:
  US11/782,535
• Publication Number:
  US 20070267699A1
• Time in Patent Office: 728 Days
• Field of Search: 257/43, 257/59, 257/72, 257/347, 257/E29.117, 257/E29.273, 257/49, 257/E29.053
• US Class Current: 257/43
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/105 with vertical doping variation H01L29/7827 takes precedence
• CPC Class Codes: H01L 29/1054 with a variation of the composition, e.g. channel with strained layer for increasing the mobility
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• 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 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

A transistor having a gate electrode, a source electrode, a drain electrode, a dielectric material and a channel region disposed between the source electrode and drain electrode. The channel region includes a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region.

Claims

1. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region that is not doped with the impurity and disposed between the source and drain electrode wherein the portion and the remainder are fabricated of the same underlying material; and

a dielectric material electrically separating the gate electrode from the channel region and in contact with the portion doped with the impurity;

wherein the deposited thin-film channel is capable of changing a charge density in the portion doped with the impurity.

2. The thin-film transistor of claim 1, where the portion of the channel region is disposed between the remainder of the channel region and the dielectric material.

3. The thin-film transistor of claim 1, where the dielectric material includes silicon dioxide.

4. The thin-film transistor of claim 1, where the channel region comprises a controllable electrical pathway between the source electrode and drain electrode.

5. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region that is not doped with the impurity and disposed between the source and drain electrode wherein the portion and the remainder are fabricated of the same underlying material and wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region and in contact with the portion doped with the impurity;

wherein the deposited thin-film channel is capable of changing a charge density in the portion doped with the impurity.

6. The thin-film transistor of claim 5, where the channel region is fabricated from zinc oxide.

7. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region, wherein the impurity is a donor-type impurity which increases the positive fixed charge density within the portion of the channel region.

8. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region wherein the impurity is an acceptor-type impurity which increases the negative fixed charge density within the portion of the channel region.

9. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region, where the channel region is fabricated from zinc oxide and wherein the impurity is a donor-type impurity which increases the positive fixed charge density within the portion of the channel region.

10. The thin-film transistor of claim 9, where the donor-type impurity is selected from the group consisting of aluminum, boron, gallium, indium, fluorine and chlorine.

11. The thin-film transistor of claim 9, where the donor-type impurity is aluminum.

12. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region, where the channel region is fabricated from zinc oxide and wherein the impurity is an acceptor-type impurity which increases the negative fixed charge density within the portion of the channel region.

13. The thin-film transistor of claim 12, where the acceptor-type impurity is selected from the group consisting of nitrogen, copper, phosphorous, arsenic, antimony, lithium, sodium and potassium.

14. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region, wherein the channel region is fabricated from indium oxide.

15. The thin-film transistor of claim 14, where the impurity is a donor-type impurity which increases the positive fixed charge density within the portion of the channel region.

16. The thin-film transistor of claim 15, where the donor-type impurity is selected from the group consisting of silicon, germanium, tin, lead, fluorine and chlorine.

17. The thin-film transistor of claim 14, where the impurity is an acceptor-type impurity which increases the negative fixed charge density within the portion of the channel region.

18. The thin-film transistor of claim 17, where the acceptor-type impurity is selected from the group consisting of nitrogen, phosphorous, arsenic and antimony.

19. A thin-film transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

a deposited thin-film channel region having a portion doped with an impurity to change the fixed charge density within the portion relative to a remainder of the channel region and disposed between the source and drain electrode wherein the channel region is a deposited layer fabricated from a binary oxide semiconductor material; and

a dielectric material electrically separating the gate electrode from the channel region, where the channel region is fabricated from zinc oxide and wherein the channel region is fabricated from tin oxide.

20. The thin-film transistor of claim 19, where the impurity is a donor-type impurity which increases the positive fixed charge density within the portion of the channel region.

21. The thin-film transistor of claim 20, where the donor-type impurity is selected from the group consisting of arsenic, antimony, bismuth, fluorine and chlorine.

22. The thin-film transistor of claim 19, where the impurity is an acceptor-type impurity which increases the negative fixed charge density within the portion of the channel region.

23. The thin-film transistor of claim 22, where the acceptor-type impurity is selected from the group consisting of boron, aluminum, gallium, indium, nitrogen, phosphorus, arsenic and antimony.