High-k/metal gate MOSFET with reduced parasitic capacitance
First Claim
1. A method of forming a semiconductor structure comprising:
- providing a structure including a sacrificial gate and a gate dielectric located on a semiconductor substrate, said structure further including an interlevel dielectric located on said semiconductor substrate and separated from said sacrificial gate by a sacrificial spacer;
removing the sacrificial gate and a portion of the gate dielectric that is not protected by the sacrificial spacer to form an opening that exposes a surface of the semiconductor substrate;
forming a U-shaped high-k gate dielectric and a metal-containing gate conductor inside the opening;
removing the sacrificial spacer to expose a portion of the U-shaped high-k gate dielectric that laterally abuts sidewalls of the metal-containing gate conductor;
removing substantially all of the exposed portion of the high-k gate dielectric that laterally abuts the sidewalls of the metal-containing gate conductor from the gate sidewalls; and
forming a gate spacer in an area that previously included the sacrificial spacer and a portion of the U-shaped high-k gate dielectric to provide at least one MOSFET comprising a gate stack including, from bottom to top, the high-k gate dielectric and the metal-containing gate conductor, said metal-containing gate conductor having gate corners located at a base segment of the metal-containing gate conductor, wherein said metal-containing gate conductor has vertical sidewalls devoid of said high-k gate dielectric except at said gate corners, and wherein the gate dielectric is laterally abutting said high-k gate dielectric which is present at said gate corners and said gate spacer is laterally abutting said metal-containing gate conductor and is located upon an upper surface of both the gate dielectric and the high-k gate dielectric that is present at the gate corners.
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Accused Products
Abstract
The present invention provides a high-k gate dielectric/metal gate MOSFET that has a reduced parasitic capacitance. The inventive structure includes at least one metal oxide semiconductor field effect transistor (MOSFET) 100 located on a surface of a semiconductor substrate 12. The least one MOSFET 100 includes a gate stack including, from bottom to top, a high-k gate dielectric 28 and a metal-containing gate conductor 30. The metal-containing gate conductor 30 has gate corners 31 located at a base segment of the metal-containing gate conductor. Moreover, the metal-containing gate conductor 30 has vertically sidewalls 102A and 102B devoid of the high-k gate dielectric 28 except at the gate corners 31. A gate dielectric 18 laterally abuts the high-k gate dielectric 28 present at the gate corners 31 and a gate spacer 36 laterally abuts the metal-containing gate conductor 30. The gate spacer 36 is located upon an upper surface of both the gate dielectric 18 and the high-k gate dielectric that is present at the gate corners 31.
58 Citations
6 Claims
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1. A method of forming a semiconductor structure comprising:
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providing a structure including a sacrificial gate and a gate dielectric located on a semiconductor substrate, said structure further including an interlevel dielectric located on said semiconductor substrate and separated from said sacrificial gate by a sacrificial spacer; removing the sacrificial gate and a portion of the gate dielectric that is not protected by the sacrificial spacer to form an opening that exposes a surface of the semiconductor substrate; forming a U-shaped high-k gate dielectric and a metal-containing gate conductor inside the opening; removing the sacrificial spacer to expose a portion of the U-shaped high-k gate dielectric that laterally abuts sidewalls of the metal-containing gate conductor; removing substantially all of the exposed portion of the high-k gate dielectric that laterally abuts the sidewalls of the metal-containing gate conductor from the gate sidewalls; and forming a gate spacer in an area that previously included the sacrificial spacer and a portion of the U-shaped high-k gate dielectric to provide at least one MOSFET comprising a gate stack including, from bottom to top, the high-k gate dielectric and the metal-containing gate conductor, said metal-containing gate conductor having gate corners located at a base segment of the metal-containing gate conductor, wherein said metal-containing gate conductor has vertical sidewalls devoid of said high-k gate dielectric except at said gate corners, and wherein the gate dielectric is laterally abutting said high-k gate dielectric which is present at said gate corners and said gate spacer is laterally abutting said metal-containing gate conductor and is located upon an upper surface of both the gate dielectric and the high-k gate dielectric that is present at the gate corners. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification