Semiconductor device including polysilicon resistor and metal gate resistor and methods of fabricating thereof
First Claim
1. A method, comprising:
- forming a polysilicon layer on a semiconductor substrate;
etching the polysilicon layer to form a first region having a first height from a top surface of the semiconductor substrate and a second region having a second height from the top surface of the semiconductor substrate, wherein the second height is less than the first height;
forming a first gate structure on the semiconductor substrate, wherein the first gate structure is formed of the second region of the etched polysilicon layer and is disposed over an isolation region of the substrate;
forming a sacrificial gate structure on the semiconductor substrate adjacent the first gate structure, wherein the sacrificial gate structure is formed using the first region of the etched polysilicon layer and is disposed over an active region of the substrate adjacent the isolation region; and
forming a dielectric layer overlying the first gate structure and the sacrificial gate structure, wherein the dielectric layer has a first thickness above a top surface of the first gate structure and a second thickness above a top surface of the sacrificial gate structure, wherein the second thickness is less than the first thickness;
after forming the dielectric layer, performing a planarization process on the dielectric layer to expose the top surface of the sacrificial gate structure, wherein after performing the planarization process a portion of the dielectric layer having a third thickness remains above the first gate structure;
after the planarization process, removing the sacrificial gate structure to form a trench;
forming a metal gate structure in the trench; and
forming a first contact to the first gate structure and forming a second contact to the metal gate structure.
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Accused Products
Abstract
A described method includes providing a semiconductor substrate. A first gate structure is formed on the semiconductor substrate and a sacrificial gate structure formed adjacent the first gate structure. The sacrificial gate structure may be used to form a metal gate structure using a replacement gate methodology. A dielectric layer is formed overlying the first gate structure and the sacrificial gate structure. The dielectric layer has a first thickness above a top surface of the first gate structure and a second thickness, less than the first thickness, above a top surface of the sacrificial gate structure. (See, e.g., FIGS. 5, 15, 26). Thus, a subsequent planarization process of the dielectric layer may not contact the first gate structure.
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Citations
18 Claims
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1. A method, comprising:
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forming a polysilicon layer on a semiconductor substrate; etching the polysilicon layer to form a first region having a first height from a top surface of the semiconductor substrate and a second region having a second height from the top surface of the semiconductor substrate, wherein the second height is less than the first height; forming a first gate structure on the semiconductor substrate, wherein the first gate structure is formed of the second region of the etched polysilicon layer and is disposed over an isolation region of the substrate; forming a sacrificial gate structure on the semiconductor substrate adjacent the first gate structure, wherein the sacrificial gate structure is formed using the first region of the etched polysilicon layer and is disposed over an active region of the substrate adjacent the isolation region; and forming a dielectric layer overlying the first gate structure and the sacrificial gate structure, wherein the dielectric layer has a first thickness above a top surface of the first gate structure and a second thickness above a top surface of the sacrificial gate structure, wherein the second thickness is less than the first thickness; after forming the dielectric layer, performing a planarization process on the dielectric layer to expose the top surface of the sacrificial gate structure, wherein after performing the planarization process a portion of the dielectric layer having a third thickness remains above the first gate structure; after the planarization process, removing the sacrificial gate structure to form a trench; forming a metal gate structure in the trench; and forming a first contact to the first gate structure and forming a second contact to the metal gate structure. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method, comprising:
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providing a substrate having a first surface; forming a recess in an isolation region of the substrate, thereby providing a recessed region having a second surface of dielectric material spaced a distance from the first surface, wherein the recess is defined by a first sidewall edge of dielectric material and an opposing second sidewall edge of dielectric material, wherein first and second active regions having a top surface of the first surface interpose the first sidewall edge and second sidewall edge such that the recess having the second surface is disposed between the first and second active regions and on opposing sides of each of the first and second isolation features; forming a polysilicon gate structure in the recess on the second surface and interposing the first and second active regions; forming a first sacrificial gate structure on the first surface in the first active region; forming a second sacrificial gate structure on the first surface in the isolation region and adjacent the second sidewall edge of the recess; and forming a dielectric layer overlying the polysilicon gate structure, the first sacrificial gate structure and the second sacrificial gate structure. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method, comprising:
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providing a substrate having a polysilicon layer; doping the polysilicon layer, wherein the doping includes a shallow implant of a first dopant type and a deep implant of a second dopant type, thereby forming a top portion of the polysilicon being a first dopant type-rich portion and an underlying portion of the polysilicon being a second dopant type-rich portion; etching a recess in the polysilicon layer, after the doping, to provide a first portion having a first thickness and a second portion having a second thickness, the second thickness being less than the first thickness, wherein the etching the recess includes using the second dopant type-rich portion of the polysilicon layer as an etch stop; after etching the polysilicon layer, patterning the polysilicon layer to form a first gate structure and a second gate structure, wherein the first gate structure is formed in the first portion of the polysilicon and the second gate structure is formed in the second portion of the polysilicon layer; removing the first gate structure to form an opening; forming a metal gate structure in the opening; and forming contacts to each of the metal gate structure and the second gate structure. - View Dependent Claims (15, 16, 17, 18)
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Specification