Methods for depositing fluorine/carbon-free conformal tungsten
Provided are atomic layer deposition methods to deposit a tungsten film or tungsten-containing film using a tungsten-containing reactive gas comprising one or more of tungsten pentachloride, a compound with the empirical formula WCl 5 or WCl 6 .
1. A method of depositing a WSi x N y film, the method comprising
positioning a substrate in a processing chamber; and
sequentially exposing at least a portion of the substrate to a first reactive gas and a second reactive gas at a temperature less than or equal to about 475° C. to form the WSi x N y film,
wherein the first reactive gas comprises one or more of tungsten pentachloride, a compound with the empirical formula W x Cl 5x or tungsten hexachloride and the second reactive gas comprises a silicon-containing gas and a nitrogen-containing compound.
2. The method of claim 1 , wherein the substrate comprises a work function metal.
3. The method of claim 2 , wherein the work function metal comprises Ti or TiAl.
4. The method of claim 1 , wherein prior to deposition of the WSi x N y film, the substrate comprises an oxide layer and the method further comprises soaking the substrate with a hydride or a mixture of hydrogen and a hydride.
5. The method of claim 4 , wherein the hydride comprises one or more of a silane compound, a borane compound or phosphine.
6. The method of claim 4 , wherein the substrate is soaked for a time period in a range of 1 second to 90 seconds.
7. The method of claim 1 , wherein the WSi x N y film grows at a rate in the range of 0.1 Å/cycle and 5 Å/cycle.
8. The method of claim 1 , wherein the temperature is in a range of 300° C. to 475° C.
9. A method of forming a conformal tungsten film comprising sequentially exposing a surface to a first reactive gas comprising a tungsten-containing compound for a first time and a second reactive gas comprising hydrogen, a silicon-containing compound and a nitrogen-containing compound for a second time, the first time and the second time being less than about 2 second to deposit a tungsten-containing film comprises tungsten-silicon-nitride (WSi x N y ) and having a thickness in the range of about 10 Å to about 30 Å, the tungsten-containing compound comprising one or more of a compound having the empirical formula W x Cl 5x or tungsten hexachloride.
10. The method of claim 9 , wherein the tungsten-containing film is grown at a rate less than about 1 Å/cycle.
11. The method of claim 9 , wherein the tungsten-containing film is grown at a rate less than about 0.8 Å/cycle.
12. The method of claim 9 , wherein prior to deposition of the tungsten-containing film, the substrate comprises a metallic layer.
13. The method of claim 9 , wherein prior to deposition of the tungsten-containing film, the substrate comprises an oxide layer and the method further comprises soaking the substrate with disilane or a mixture of hydrogen and silane at a partial pressure in the range of about 5 to about 20 Torr.
14. The method of claim 9 , wherein the tungsten-containing film grows at a rate in the range of about 0.2 Å/cycle and about 3 Å/cycle.