Tungsten deposition without barrier layer
Methods for depositing a metal film without the use of a barrier layer are disclosed. Some embodiments comprise forming an amorphous nucleation layer comprising one or more of silicon or boron and forming a metal layer on the nucleation layer.
1. A processing method comprising:
exposing a substrate surface to a silicon precursor and a boron precursor to form an amorphous layer comprising silicon and boron, the substrate surface being substantially free of a barrier layer, the amorphous layer comprising no more than 5 atomic percent silicon or no more than 5 atomic percent boron;
exposing the amorphous layer to a first metal precursor to convert the amorphous layer to a first metal layer; and
forming a second metal layer on the first metal layer by exposing the first metal layer to a second metal precursor.
2. The method of claim 1 , wherein the silicon precursor comprises one or more species with a general formula of Si g H h X i , where each X is a halogen independently selected from F, Cl, Br and I, g is any integer greater than or equal to 1, h and i are each less than or equal to 2g+2 and h+i is equal to 2g+2.
3. The method of claim 1 wherein the amorphous layer comprises no more than 5 atomic percent silicon.
4. The method of claim 1 wherein the amorphous layer comprises no more than 5 atomic percent boron.
5. The method of claim 1 , wherein the first metal precursor comprises one or more of WF 6 , WCl 6 , MoF 6 , MoCl 5 , or Mo(CO) 6 .
6. The method of claim 1 , wherein the second metal layer is formed by separately exposing the substrate surface to a second metal precursor and a reactant.
7. The method of claim 1 , wherein the boron precursor comprises one or more species with a general formula of B c H d X e R f , where each X is a halogen independently selected from F, Cl, Br and I, each R is an independently selected C1-C4 alkyl group, c is any integer greater than or equal to 2, each of d, e and f are less than or equal to c+2 and d+e+f is equal to c+2.
8. The method of claim 1 , wherein the second metal precursor comprises one or more of WF 6 , WCl 6 , MoF 6 , MoCl 5 , or Mo(CO) 6 .
9. The method of claim 1 , wherein the first metal precursor comprises substantially no fluorine.
10. The method of claim 1 , wherein the first metal precursor and the second metal precursor comprise the same metal.