Atomic layer deposition of P-type oxide semiconductor thin films

Patent metadata

Field	Value
Publication number	US-9685542-B2
Application number	US-201414586282-A
Country	US
Kind code	B2
Filing date	Dec 30, 2014
Priority date	Dec 30, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Provided herein are methods of depositing p-type metal oxide thin films by atomic layer deposition (ALD). Also provided are p-type metal oxide thin films and TFTs including p-type metal oxide channels. In some implementations, the p-type metal oxide thin films have a metal and oxygen vacancy defect density of less than 10 19 /cm 3 . The p-type metal oxide thin films may be electrically active throughout the entire thicknesses of the thin films.

First claim

What is claimed is:

1. A method of forming a thin film transistor (TFT) comprising:
providing a substrate;
exposing the substrate to a pulse of a first reactant to form an adsorbed layer of the first reactant over the substrate;
exposing the substrate to a pulse of a second reactant to react with the first reactant; and
exposing the substrate to a pulse of an oxidant to form a metal oxide layer, where the metal oxide layer is a tin-based (Sn-based) p-type semiconductor layer including a ternary compound Sn(II)—X—O that includes Sn—X bonds, wherein X is one of titanium (Ti), tungsten (W), boron (B), or niobium (Nb).

2. The method of claim 1 , wherein the first reactant is an Sn(II)-based organometallic reactant.

3. The method of claim 1 , wherein the substrate temperature is between about 50° C. and 300° C.

4. The method of claim 1 , wherein the oxidant is selected from the group consisting of oxygen (O 2 ), ozone (O 3 ), water (H 2 O), hydrogen peroxide (H 2 O 2 ), carbon dioxide (CO 2 ), carbon monoxide (CO), methanol (CH 3 OH), ethanol (C 2 H 6 OH), isopropyl alcohol (C 3 H 7 OH), and combinations thereof.

5. The method of claim 1 , wherein the oxidant is a hydrogen-containing oxidant.

6. The method of claim 5 , wherein hydrogen from the hydrogen-containing oxidant is incorporated in the metal oxide layer.

7. The method of claim 1 , wherein the oxidant is a weak oxidant.

8. The method of claim 1 , wherein exposing the substrate to a pulse of an oxidant includes applying energy to the pulse of the oxidant to form a plasma.

9. The method of claim 1 , wherein the second reactant is selected from the group consisting of tungsten-containing reactants, titanium-containing reactants, niobium-containing reactants, and boron-containing reactants.

10. The method of claim 1 , further comprising exposing the substrate to a dopant pulse.

11. The method of claim 10 , wherein the dopant is hydrogen.

12. The method of claim 1 , further comprising forming a gate electrode and a gate dielectric, wherein the gate dielectric is between the p-type semiconductor layer and the gate electrode.

13. The method of claim 12 , wherein the gate electrode is formed over the metal oxide layer.

14. The method of claim 12 , wherein the metal oxide layer is formed over the gate electrode.

15. The method of claim 1 , wherein the exposing the substrate to a pulse of the second reactant forms an adsorbed layer of the second reactant on the substrate surface.

16. A method of forming a thin film transistor (TFT) comprising:
providing a substrate;
exposing the substrate to a pulse of a metal reactant to form an adsorbed layer of the metal reactant over the substrate;
exposing the substrate to a pulse of an oxidant to react with the adsorbed layer of the metal reactant to form a metal oxide layer, wherein the metal oxide layer is a tin(II)-based p-type semiconductor layer having substantially no tin(IV); and
incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer, wherein incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer includes exposing the substrate to a hydrogen-containing atmosphere during the metal reactant and oxidant pulses.

17. The method of claim 16 , wherein the oxidant is a hydrogen-containing oxidant.

18. The method of claim 16 , wherein incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer includes exposing the substrate to dopant pulses to incorporate hydrogen into the metal oxide layer.

19. The method of claim 16 , wherein incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer includes annealing the metal oxide layer in a hydrogen atmosphere.

20. A method of forming a thin film transistor (TFT) comprising:
providing a substrate;
exposing the substrate to a pulse of a metal reactant to form an adsorbed layer of the metal reactant over the substrate;
exposing the substrate to a pulse of an oxidant to react with the adsorbed layer of the metal reactant to form a metal oxide layer, wherein the metal oxide layer is a tin(II)-based p-type semiconductor layer having substantially no tin(IV); and
incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer, wherein the oxidant is a hydrogen-containing oxidant and incorporating a hydrogen content of at least 10 20 atoms/cm 3 into the metal oxide layer includes applying energy to the pulse of the hydrogen-containing oxidant to form a plasma and incorporating hydrogen from the plasma into the metal oxide layer.

Assignees

• Snaptrack Inc
• Qualcomm Inc

Inventors

• Nomura Kenji
• Hong John Hyunchul

Classifications

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/3412

  including tin · CPC title

• H10P14/2922 Primary

  being non-crystalline insulating materials, e.g. glass or polymers · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title

• C23C16/407

  of zinc, germanium, cadmium, indium, tin, thallium or bismuth · CPC title