Plasma nitridation for reduced leakage gate dielectric layers
AssigneeIntel Corporation
InventorsRobert McFadden, Jack Kavalieros, Reza Arghavani, Doug Barlage, Robert Chau
Life of this patent
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Abstract
A method of forming a dielectric layer suitable for use as the gate dielectric layer in a MOSFET includes nitridizing a thin silicon oxide film in a low power, direct plasma formed from nitrogen. A gas having a lower ionization energy than nitrogen, such as for example, helium, may be used in combination with nitrogen to produce a lower power plasma resulting in a steeper concentration curve for nitrogen in the silicon oxide film.
Claims23
An method of nitiridizing an oxide of silicon, comprising:
- exposing the oxide to a direct plasma, the plasma formed from at least nitrogen.
A field effect transistor, comprising:
- a gate electrode;
- a pair of source/drain terminals disposed in a substrate, substantially adjacent the gate electrode;
- and
- a gate dielectric disposed between the gate electrode and the substrate, the gate dielectric comprising an oxide of silicon less than or equal 10 angstroms in thickness and having nitrogen disposed therein, the concentration decreasing from a gate electrode-gate dielectric interface to a gate dielectric-substrate interface.
A method of forming a gate dielectric layer on a surface of a substrate, comprising:
- growing an oxide of silicon on the surface of the substrate;
- disposing the substrate between a heatable susceptor and a cathode of a parallel plate plasma reactor such that the substrate is supported and heated by the susceptor, and adjusting a spacing between the susceptor and cathode such that the spacing is between 0.4 and 1.6 cm;
- flowing N2 and a gas having a lower ionization energy than N2;
- igniting a plasma;
- and
- introducing nitrogen into the oxide by direct ionic bombardment.
The method of claim 16, further comprising maintaining a pressure in the plasma reactor between 0.5 and 4 torr.
A method of making a field effect transistor, comprising:
- forming an oxide layer on a substrate;
- nitridizing the oxide layer in a low power direct plasma formed from nitrogen and helium;
- forming a gate electrode layer over the nitridized oxide layer;
- patterning the gate electrode layer to form a gate electrode having opposing sidewalls;
- and
- forming source/drain terminals substantially adjacent the opposing sidewalls of the gate electrode.
Dependencies are inferred from the claim text.