Hatted polysilicon gate structure for improving salicide performance and method of forming the same
First Claim
Patent Images
1. A method of forming a low resistance salicided gate structure of a field effect transistor, comprising the following steps:
- forming a pair of vertical spacers over a substrate, said spacers defining a gate trench region having a gate dielectric layer formed therein;
depositing a blanket layer of polysilicon over said spacers and in said gate trench region;
planarizing said deposited layer of polysilicon;
selectively etching said planarized polysilicon layer to form a polysilicon gate element having a generally trapezoidal shaped polysilicon region over said gate trench, wherein a base of said trapezoidal region at least partially overlaps said spacers; and
forming a silicide contact in said trapezoidal region.
1 Assignment
0 Petitions
Accused Products
Abstract
Alternate methods of forming low resistance “hatted” polysilicon gate elements are provided that increase the effective area in the polysilicon gate for silicide grain growth during silicide formation. The expanded top portion helps to prevent silicide agglomeration in the silicide regions, thereby maintaining or reducing electrode resistance, improving high-frequency performance, and reducing gate delay in sub micron FET ULSI devices, without increasing the underlying active channel length.
10 Citations
29 Claims
-
1. A method of forming a low resistance salicided gate structure of a field effect transistor, comprising the following steps:
-
forming a pair of vertical spacers over a substrate, said spacers defining a gate trench region having a gate dielectric layer formed therein;
depositing a blanket layer of polysilicon over said spacers and in said gate trench region;
planarizing said deposited layer of polysilicon;
selectively etching said planarized polysilicon layer to form a polysilicon gate element having a generally trapezoidal shaped polysilicon region over said gate trench, wherein a base of said trapezoidal region at least partially overlaps said spacers; and
forming a silicide contact in said trapezoidal region. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
- 8. An integrated circuit including a field effect transistor having a salicided gate element structure, wherein said transistor includes a polysilicon gate element formed between a pair of vertical spacers defining a gate trench, said polysilicon gate element having a generally trapezoidal shaped region formed over said gate trench and at least partially overlapping said spacers, said trapezoidal shaped region having a silicide contact formed therein.
-
15. A method of forming a low resistance salicided gate structure of a field effect transistor, comprising the following steps:
-
etching an insulating layer deposited over a substrate to define a gate trench region of said transistor, said gate trench region having a gate dielectric layer formed therein;
depositing a blanket layer of polysilicon over said insulating layer and within said gate trench region;
planarizing said blanket layer of polysilicon;
etching said planarized layer of polysilicon and said insulating layer to form a generally T-shaped polysilicon gate element and a pair of vertical spacers including a portion of said insulating layer, said generally T-shaped polysilicon gate element at least partially overlapping said spacers; and
forming a silicide contact in said T-shaped polysilicon gate element. - View Dependent Claims (16, 17, 19, 20, 21, 22)
-
-
18. The method of claim 18, wherein said metal layer includes tantalum, tungsten, titanium, cobalt or nickel.
-
23. A method of forming a low resistance salicided gate structure of a field effect transistor, comprising the following steps:
-
forming a pair of vertical spacers over a substrate, said spacers defining a gate trench region having a gate dielectric layer formed therein;
depositing a blanket layer of polysilicon over said spacers and in said gate trench region;
planarizing said deposited layer of polysilicon;
selectively etching said planarized polysilicon layer to form a polysilicon gate element having a generally trapezoidal shaped polysilicon region over said gate trench, wherein a base of said trapezoidal region at least partially overlaps each of said spacers; and
depositing a layer of cobalt over said trapezoidal region and processing said cobalt layer to form a cobalt silicide contact in said trapezoidal region, wherein said trapezoidal region is sized to substantially prevent silicide agglomeration in said cobalt silicide contact. - View Dependent Claims (24, 25)
-
-
26. A method of forming a low resistance salicided gate structure of a field effect transistor, comprising the following steps:
-
etching an insulating layer deposited over a substrate to define a gate trench region of said transistor, said gate trench region having a gate dielectric layer formed therein;
depositing a blanket layer of polysilicon over said insulating layer and within said gate trench region;
planarizing a top surface of said blanket layer of polysilicon;
etching said planarized layer of polysilicon and said insulating layer to form a generally T-shaped polysilicon gate element and a pair of vertical spacers including a remaining portion of said insulating layer, said T-shaped polysilicon gate element at least partially overlapping each of said spacers; and
depositing a layer of cobalt over said polysilicon gate element and processing said cobalt layer to form a cobalt silicide contact in a top portion of said polysilicon gate element, wherein said top portion is sized to substantially prevent silicide agglomeration in said cobalt silicide contact. - View Dependent Claims (27, 28, 29)
-
Specification