Process for depositing a low resistivity tungsten silicon composite film on a substrate

Abstract

Abstract A composite film is provided which has a first layer of WSi x , where x is greater than 2, over which is disposed a second layer of a tungsten complex consisting substantially of tungsten with a small amount of silicon therein, typically less than 5%. Both layers are deposited in situ in a cold wall chemical vapor deposition chamber at a substrate temperature of between 500° and 550° C. Before initiating the deposition process for these first and second layers, the substrate onto which they are to be deposited is first plasma etched with NF 3 as the reactant gas, then with H 2 as the reactant gas, both steps being performed at approximately 100 to 200 volts self-bias. WSi x is then deposited onto the surface of the substrate using a gas flow rate for silane which is 20 to 80 times the flow rate of tungsten silicide, followed by deposition of a tungsten complex as the second layer, using a gas flow rate for tungsten hexafluoride which is 1 to 3 times the flow rate of silane, and a gas flow rate of hydrogen which is about 10 times the flow rate of silane. Similarly, in another embodiment, the tungsten complex without the silicide layer is deposited directly onto a silicon surface using the same process as for the tungsten complex in the second layer of the first embodiment.

Inventors

• 👤 Daniel L. Brors

Bibliographic Details