Methods of forming conformal transition metal dichalcogenide films for memory and logic applications
Transition metal dichalcogenide films and methods for depositing transition metal dichalcogenide films on a substrate are described. Methods for converting transition metal oxide films to transition metal dichalcogenide films are also described. The substrate is exposed to a metal precursor and an oxidant to form a transition metal oxide film; the transition metal oxide film is exposed to a chalcogenide precursor to form the transition metal dichalcogenide film.
1 . A method of forming a transition metal dichalcogenide film, the method comprising:
depositing a transition metal oxide film on a substrate surface by sequentially exposing the substrate surface to a metal precursor, purge gas, an oxidant comprising one or more of H 2 O, O 2 , or O 3 , and the purge gas; and
converting the transition metal oxide film to the transition metal dichalcogenide film, wherein the transition metal dichalcogenide film is a channel material in a 3D NAND device, and the method is a thermal method that is performed without the use of plasma.
2 . The method of claim 1 , wherein the substrate surface does not contain a barrier layer.
3 . The method of claim 1 , wherein the substrate surface is maintained at a temperature in a range of about 350° C. to about 450° C.
4 . The method of claim 1 , wherein the substrate surface comprises a dielectric material.
5 . The method of claim 1 , wherein the substrate surface comprises at least one feature with an aspect ratio greater than or equal to about 10:1.
6 . The method of claim 1 , wherein depositing the transition metal oxide film comprises directly forming the transition metal oxide film without forming a transition metal film intermediate.
7 . The method of claim 1 , wherein the metal precursor does not comprise oxygen or halogen atoms.
8 . The method of claim 1 , wherein the metal precursor comprises bis(t-butylimino) bis(dimethylamino) tungsten or bis(t-butylimino) bis(dimethylamino)molybdenum.
9 . The method of claim 1 , wherein converting the transition metal oxide film is performed at a pressure in a range of from 5 Torr to 20 Torr.
10 . The method of claim 1 , wherein converting the transition metal oxide film to the transition metal dichalcogenide film comprises exposing the transition metal oxide film to a chalcogenide precursor comprising one or more of sulfur(S), selenium (Se) or tellurium (Te).
11 . The method of claim 10 , wherein the chalcogenide precursor comprises H 2 S.
12 . The method of claim 1 , wherein 20 Å to 30 Å of the transition metal oxide film is formed before converting the transition metal oxide film.
13 . The method of claim 1 , wherein only a monolayer of the transition metal oxide film is formed before converting the transition metal oxide film.
14 . The method of claim 13 , wherein the method is repeated to form the transition metal dichalcogenide film to a thickness in a range of 20 Å to 30 Å.
15 . The method of claim 1 , wherein the transition metal dichalcogenide film is substantially free of oxygen.
16 . The method of claim 1 , wherein the substrate surface comprises at least one feature and the transition metal dichalcogenide film is substantially conformal over the at least one feature.
17 . The method of claim 1 , wherein depositing the transition metal oxide film on the substrate surface and converting the transition metal oxide film to the transition metal dichalcogenide film are performed in a single processing chamber.
18 . A method of forming a transition metal dichalcogenide film on a substrate surface comprising at least one feature, the method comprising:
sequentially exposing the substrate surface to a metal precursor, purge gas, an oxidant, and the purge gas to directly deposit a transition metal oxide film, the metal precursor comprising bis(t-butylimino) bis(dimethylamino) tungsten or bis(t-butylimino) bis(dimethylamino) molybdenum, the transition metal oxide film being substantially conformal over the at least one feature;
exposing the transition metal oxide film to a chalcogenide precursor to convert the transition metal oxide film to the transition metal dichalcogenide film, the chalcogenide precursor comprising H 2 S, wherein converting the transition metal oxide film is performed at a pressure of 1 Torr, the transition metal dichalcogenide film is a channel material in a 3D NAND device and has a thickness in a range of 20 Å to 30 Å, the substrate surface is maintained at a temperature in a range of about 350° C. to about 450° C., and the method is a thermal method that is performed without the use of plasma.