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US 5,358,879 AGranted
Method of making gate overlapped lightly doped drain for buried channel devices
AssigneeLoral Federal Systems Company
InventorsFrederick T. Brady, Charles P. Breiten, Nadium F. Haddad, William G. Houston, Oliver S. Spencer, Steven J. Wright
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Abstract
A process to form poly sidegate LDD structures on buried channel MOSFETs is described. A polysilicon spacer is formed on the gate after source/drain processing. The spacer is later shorted to the main gate by implantation of neutral impurities. The process is particularly suited for SOI technology.
Claims3
A method of fabricating a semiconductor device, comprising the steps of:
- forming a transistor structure having a gate electrode, source and drain regions and a gate oxide on a semiconductor substrate;
- forming a nitride cap on an oxide layer over the gate electrode;
- implanting first ions into the substrate to form an LDD layer in the substrate;
- forming a nitride spacer over the gate electrode;
- implanting second ions into the substrate to form source and drain regions containing the LDD layer;
- stripping nitride cap and spacer material;
- forming a polysilicon sidegate adjacent to the gate electrode;
- forming a second nitride spacer adjacent to the polysilicon sidegates;
- and
- implanting heavy ions of a neutral conductivity type in silicon into the gate region to electrically short the gate electrode and polysilicon sidegate together.
7 more elements
Dependencies are inferred from the claim text.