Method of depositing tungsten on silicon in a non-self-limiting CVD process and semiconductor device manufactured thereby
AssigneeInternational Business Machines Corporation
InventorRajiv V. Joshi
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Abstract
A method of depositing tungsten on a substrate utilizing silicon reduction wherein the process is non-limiting as to the thickness of silicon that may be converted to tungsten. A silicon substrate is provided with at least one area of silicon material having a predetermined thickness and the substrate is exposed to a tungsten hexafluoride gas flow in a chemical vapor deposition environment. By adjusting the WF.sub.6 gas flow rate and the CVD process parameters, such as pressure, temperature and deposition time, the thickness of silicon converted to tungsten can be adjusted in order to convert the entire thickness. A novel structure having a midgap tungsten gate and tungsten source and drain metallized layers is also disclosed.
Claims3
A metal oxide semiconductor device comprising:
- a semiconductor layer of a first conductivity type;
- drain and source regions of a second conductivity type formed in said semiconductor layer, said drain and source regions being separated from each other;
- an oxide insulating layer formed on said semiconductor layer between said source and drain regions;
- a refractory metal gate layer formed on said oxide insulating layer, said refractory metal gate layer having first and second sidewalls of an insulating material;
- source and drain refractory metal layers formed on said source and drain regions respectively, said source refractory metal layer having first and second sidewall spacers of an insulating material and said drain refractory metal layer having third and fourth sidewall spacers of an insulating material, said second and third sidewall spacers being spaced from each other and contiguous with said first and second gate sidewalls respectively;
- and
- ohmic contacts formed on said source and drain refractory metal layers.
Dependencies are inferred from the claim text.