Methods to deposit controlled thin layers of transition metal dichalcogenides

1. A method of preparing a substrate comprising:

performing an a atomic layer deposition cycle exposure for a transition metal precursor at a first deposition temperature between 50° C. and 300° C. above a sublimation temperature of the transition metal precursor;

performing a b atomic layer deposition cycle exposure for a sulfur precursor at a second deposition temperature between 50° C. and 300° C. above a sublimation temperature of the sulfur precursor;

performing z supercycles of the a atomic layer deposition cycle and of the b atomic layer deposition cycle; and

forming a transition metal dichalcogenide coating;

wherein the transition metal precursor comprises MoF 6 and the sulfur precursor is H 2 S with the transition metal dichalcogenide being MoS 2 or wherein the transition metal precursor is tetrakis(dimethylamido) hafnium or HfCl 4 and the sulfur precursor is H 2 S, with the transition metal dichalcogenide being HfS 2 .

2. The method of claim 1 , wherein the a cycles each comprise:

a 1 second dose followed by a gas purge.

3. The method of claim 1 , wherein the b cycle depositions each comprise:

a 1 second dose followed by a second gas purge.

4. The method of claim 1 , wherein the first deposition temperature and the second disposition temperature are the same.

5. The method of claim 1 , wherein the first deposition temperature is between 100° C. and 300° C.

6. The method of claim 1 , wherein the second deposition temperature is between 50° C. and 300° C.

7. The method of claim 1 , further comprising, after forming the transition metal dichalcogenide:

performing a c atomic layer deposition cycle of a second transition metal precursor at a third deposition temperature between 100° C. and 300° C.;

performing a d atomic layer deposition cycle of a second reducing precursor at a fourth deposition temperature between 100° C. and 300° C., and

performing y supercycles of the c atomic layer deposition cycle and of the d atomic layer deposition cycle, forming a transition metal coating on the transition metal dichalcogenide.

8. A method of forming a transition metal oxide and transition metal dichalcogenide stack comprising:

exposing a first transition metal precursor at a first deposition temperature between 50° C. and 400° C.;

exposing an oxidizing precursor at a second deposition temperature between 50° C. and 400° C.;

depositing a layer of transition metal oxide;

exposing a second transition metal precursor at a third deposition temperature between 50° C. and 400° C.;

exposing a sulfur precursor at a fourth deposition temperature between 50° C. and 400° C.; and

depositing a transition metal dichalcogenide on the transition metal oxide;

wherein the second transition metal precursor is tetrakis(dimethylamido) hafnium or HfCl 4 and the sulfur precursor is H 2 S, with the transition metal dichalcogenide being HfS 2 .

9. The method of claim 8 , wherein the first transition metal precursor and the second transition metal precursor are different.

10. The method of claim 8 , wherein the first transition metal precursor and the second transition metal precursor are the same.