Process for atomic layer deposition

• US 7,851,380 B2
• Filed: 09/26/2007
• Issued: 12/14/2010
• Est. Priority Date: 09/26/2007
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Cowdery-Corvan, Peter J., Nelson, Shelby F., Ellinger, Carolyn R., Levy, David H., Irving, Lyn M., Freeman, Diane C.
• Primary Examiner(s): Garber; Charles D
• Assistant Examiner(s): Isaac; Stanetta D
• Application Number:
  US11/861,491
• Publication Number:
  US 20090081842A1
• Time in Patent Office: 1,175 Days
• Field of Search: 438/763, 257/E21.171, 257/E21.409
• US Class Current: 438/763
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C23C 16/407 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 16/45551 for relative movement of the substrate and the gas injectors or half-reaction reactor compartments
• CPC Class Codes: C23C 16/45595 Atmospheric CVD gas inlets with no enclosed reaction chamber
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• 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 27/1259 Multistep manufacturing methods

Abstract

The present invention relates to a process of making thin film electronic components and devices, such as thin film transistors, environmental barrier layers, capacitors, insulators and bus lines, where most or all of the layers are made by an atmospheric atomic layer deposition process.

Claims

1. A process of making a thin film transistor comprising at least five layers including a gate layer, a dielectric layer, a channel layer, a source-drain layer, and a protective layer, wherein at least three of the five layers are grown on a substrate by an atomic layer deposition process that is carried out substantially at or above atmospheric pressure, wherein the temperature of the substrate during deposition is under 300°

C., and wherein the atomic layer deposition process comprises simultaneously directing a series of gas flows comprising, in order, at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material through a plurality of output openings spaced apart from the substrate, and transporting the substrate in a direction relative to the plurality of output openings, and such that any point on the substrate experiences a sequence of the first, the second and the third gaseous materials and whereby the sequence causes a layer to be formed by atomic layer deposition,

wherein the atomic layer deposition is carried out using a deposition system that comprises a delivery head and a means for maintaining a substantially uniform distance between the depositing output face of a delivery head and a surface of the substrate during thin film deposition, wherein the delivery head is designed to provide flows of one or more of the gaseous materials to the surface of the substrate for thin film deposition that also provides at least part of a force separating the depositing output face of the delivery head from the surface of the substrate, wherein the deposition system optionally includes an entrance section or an exit section that comprises a non-depositing output face having a plurality of non-depositing output openings designed to provide gas flow of non-reactive gas to the surface of the substrate during at least part of the passage through the deposition system.

2. The process of claim 1 wherein, during the deposition of the channel layer, the first reactive gaseous material is a volatile organo-zinc precursor compound comprising both zinc and organic groups, to produce a zinc-oxide-based thin film semiconductor.

3. The process of claim 2 wherein a volatile acceptor dopant precursor is introduced into the first reactive gaseous material, the second reactive gaseous material, the inert purge gas, or an additional gas flow of a supplemental gaseous material during formation of the channel layer, whereby the volatile acceptor dopant precursor reacts and is incorporated as an acceptor dopant in an n-type zinc-oxide-based thin film semiconductor.

4. The process of claim 3 wherein the volatile acceptor dopant precursor comprises an element selected from the group consisting of N, P, As, Li, Na, K, Cu, Ag, or mixtures thereof.

5. The process of claim 3 wherein the volatile acceptor dopant precursor comprises nitrogen in the form of NO, N₂O, NO₂, or ammonia.

6. The process of claim 1 wherein the gate layer, the dielectric layer for the gate layer, the channel layer, the source-drain layer, and the protective layer are grown by the atomic layer deposition process.

7. The process of claim 1 wherein the dielectric layer, the channel layer, and the protective layer are grown by the atomic layer deposition process.

8. The process of claim 1 wherein the gate layer, the dielectric layer, the channel layer, and the protective layer are grown by the atomic layer deposition process.

9. The process of claim 1 wherein at least three of said five layers are oxide layers.

10. The process of claim 1 wherein the gate layer is grown by the atomic layer deposition process and the gate layer is zinc oxide doped with an element selected from iridium, aluminum, boron, and fluorine.

11. The process of claim 1 wherein the source-drain layer is grown by the atomic layer deposition process and the source-drain layer is zinc oxide doped with an element selected from indium, aluminum, boron, and fluorine.

12. The process of claim 1 wherein the gate layer is grown by the atomic layer deposition process and the gate layer is a metal and wherein the source-drain layer is grown by the atomic layer deposition process and the source-drain layer is a metal.

13. The process of claim 1 wherein the series of gas flows are provided by a deposition device comprising, facing the substrate in plan view, a series of open elongated output openings, in parallel, positioned to the substrate in close proximity thereto, in an output face of the deposition device, which output face is spaced within 1 mm from a substrate surface subject to deposition.

14. The process of claim 13 wherein a given area of the substrate is exposed to a gas flow in a channel for less than 100 milliseconds and wherein relative movement of the substrate to the deposition device is at a speed at least 0.1 cm/sec.

15. The process of claim 13 wherein the deposition device further comprises exhaust openings between substantially parallel elongated output openings for the first and the second reactive gaseous materials.

16. The process of claim 15 wherein the flows of one or more of the gaseous materials to the substrate surface for thin film deposition provides at least part of a force separating the depositing output face of a delivery head from the substrate surface.

17. The process of claim 1 wherein the substrate or a support for the substrate comprises a moving web, wherein a support maintains a surface of the substrate at a separation distance of within 0.3 mm of an output face of a deposition device.

18. The process of claim 1 wherein the deposition system further comprises:

(A) an entrance section;

(B) a coating section comprising;

(i) a plurality of sources for, respectively, a plurality of gaseous materials comprising at least a first, a second, and a third source for a first, a second, and a third gaseous material, respectively;

(ii) a delivery head for delivering the plurality of gaseous materials to a substrate receiving thin film deposition, the delivery head comprising;

(a) a plurality of inlet ports comprising at least a first, a second, and a third inlet port for receiving the first, the second, and the third gaseous material, respectively; and

(b) a depositing output face separated a distance from the substrate and comprising a plurality of substantially parallel elongated output openings for each of the first, the second, and the third gaseous materials, wherein the delivery head is designed to deliver the first, the second, and the third gaseous materials simultaneously from the output openings in the depositing output face;

(C) an exit section; and

(D) means for moving the substrate in a unidirectional passage through the coating section.

19. The process of claim 18 wherein the coating section is composed of a plurality of deposition modules, wherein each deposition module in the plurality of modules at least partially contributes to a deposition function of the coating section, and wherein optionally the entrance section and/or the exit section is composed of a plurality of non-deposition modules, wherein each non-deposition module in the plurality of non-deposition modules at least partially contributes to a conveyance and/or optional physical-treatment function of the entrance or the exit section, respectively.

20. The process of claim 19 wherein the coating section is composed of at least a first and a second deposition module and wherein the first deposition module forms a thin film of a composition differing from that formed by the second deposition module.

21. The process of claim 1 wherein the process is used to make a semiconductor in a thin film transistor, wherein a thin film comprises a zinc-oxide-based material, the process comprising forming on a substrate, at a temperature of 300°

C. or less, at least one layer of a zinc-oxide-based material, wherein the zinc-oxide-based material is a reaction product of at least two reactive gases, a first reactive gas comprising an organo-zinc precursor compound and a second reactive gas comprising a reactive oxygen-containing gaseous material, and wherein the process further comprises forming a spaced apart source electrode and drain electrode, wherein the source electrode and the drain electrode are separated by, and electrically connected with, the n-type zinc-oxide-based thin film semiconductor; and

forming a gate electrode spaced apart from the n-type zinc-oxide-based thin film semiconductor.

22. The process of claim 21 comprising, not necessarily in order, the following steps:

providing the substrate;

providing a gate electrode material over the substrate;

providing a dielectric layer over the gate electrode material;

forming the n-type zinc-oxide-based thin film semiconductor over the gate dielectric; and

providing a source electrode and a drain electrode contiguous to the n-type zinc-oxide-based thin film semiconductor.

23. A process of making a thin film transistor comprising a substrate, a gate electrode, a gate dielectric, a semiconductor, a protective layer and a source electrode and a drain electrode, wherein the gate dielectric, the semiconductor and at least one of the protective layer, the gate electrode or the source and the drain electrodes are each formed by a process wherein the deposition process is an atomic layer deposition (ALD) process that is carried out substantially at or above atmospheric pressure, wherein the temperature of the substrate during deposition is under 300°

C., and wherein the ALD process comprises simultaneously directing a series of gas flows comprising, in order, at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material through a plurality of output openings spaced apart from the substrate, and transporting the substrate in a direction relative to a plurality of output openings, and such that any point on the substrate experiences a sequence of the first, the second and the third gaseous materials and whereby the sequence causes a layer to be formed by atomic layer deposition,

wherein the atomic layer deposition is carried out using a deposition system that comprises delivery a means for maintaining a substantially uniform distance between the depositing output face of the delivery head and a surface of the substrate during thin film deposition, wherein the delivery head is designed to provide flows of one or more of the gaseous materials to the surface of the substrate for thin film deposition that also provides at least part of a force separating the depositing output face of the delivery head from the surface of the substrate, wherein the deposition system optionally includes an entrance section or an exit section that comprises a non-depositing output face having a plurality of non-depositing output openings designed to provide gas flow of non-reactive gas to the surface of the substrate during at least part of the passage through the deposition system.