Conformal amorphous silicon as nucleation layer for W ALD process
Methods for depositing a metal film comprising forming an amorphous silicon layer as a nucleation layer and/or glue layer on a substrate. Some embodiments further comprise the incorporation of a glue layer to increase the ability of the amorphous silicon layer and metal layer to stick to the substrate.
1. A processing method comprising:
exposing a substrate surface to a silicon precursor to form an amorphous silicon layer having a thickness; and
forming a metal layer on the amorphous silicon layer, the metal layer comprises one or more of tungsten or molybdenum, the metal layer formed by sequentially exposing the amorphous silicon layer to a metal precursor and a reactant, the metal precursor comprising one or more of WF 6 or MoF 6 and the reactant comprising hydrogen.
2. The method of claim 1 , wherein the silicon precursor comprises a poly-silane.
3. The method of claim 2 , wherein the poly-silane comprises one or more of disilane, trisilane, tetrasilane, isotetrasilane, neopentasilane, cyclopentasilane, hexasilane or cyclohexasilane.
4. The method of claim 2 , wherein the silicon precursor comprises substantially only disilane.
5. The method of claim 1 , further comprising exposing the amorphous silicon layer to a degas environment to remove outgassed species prior to forming the metal layer.
6. The method of claim 5 , wherein the degas environment consists essentially of an inert gas.
7. The method of claim 6 , wherein the inert gas comprises one or more of argon, helium and nitrogen.
8. The method of claim 1 , wherein the thickness of the amorphous silicon layer is in the range of about 1 Å to about 100 Å.
9. The method of claim 1 , further comprising depositing a glue layer on the substrate before forming the amorphous silicon layer.
10. The method of claim 9 , wherein the glue layer comprises TiN.
11. The method of claim 10 , wherein the substrate surface comprises silicon oxide.
12. The method of claim 11 , wherein the TiN layer has a thickness in the range of about 5 Å to about 30 Å and the amorphous silicon layer has a thickness in the range of about 5 Å to about 50 Å.
13. A processing method comprising:
providing a silicon substrate having a silicon oxide surface;
forming a glue layer on the silicon substrate, the glue layer comprising TiN with a thickness in the range of about 1 Å to about 30 Å;
forming an amorphous silicon layer on the glue layer by exposing the glue layer to a silicon precursor comprising disilane, the amorphous silicon layer having a thickness in the range of about 30 Å to about 40 Å; and
forming a metal layer on the amorphous silicon layer, the metal layer comprising one or more of tungsten or molybdenum, the metal layer formed by sequentially exposing the amorphous silicon layer to a metal precursor and a reactant, the metal precursor comprising one or more of WF 6 or MoF 6 and the reactant comprising hydrogen.
14. The method of claim 13 , further comprising exposing the amorphous silicon layer to a degas environment to remove outgassed species prior to forming the metal layer.
15. The method of claim 14 , wherein the degas environment consists essentially of an inert gas.