Diffusion resistor structure with silicided contact areas, and methods of fabrication thereof

Claim 1

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure adjacent to an upper surface thereof; (b) forming a diffusion barrier layer over said semiconductor structure, said diffusion barrier layer being patterned such that a first region of said diffusion is exposed at said upper surface of said semiconductor structure, while a second region of said diffusion underlies said diffusion barrier layer; (c) forming a polysilicon layer over said diffusion barrier layer and said first region of said diffusion; (d) diffusing dopant from said first region into said polysilicon layer, thereby forming a doped polysilicon region, wherein said diffusion barrier layer prevents diffusion of said dopant from said diffusion into that portion of said polysilicon layer extending over the diffusion barrier layer, thereby defining an undoped polysilicon region; (e) forming an oxide layer over said doped polysilicon region; and (f) removing said diffusion barrier layer, and siliciding said second region of said diffusion from said upper surface of said semiconductor structure, said second region comprising a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion, wherein said first contact area comprises a first silicided contact area and said second contact area comprises a second silicided contact area, and wherein electrical contact is made to said diffusion resistor structure through said first silicided contact area and said second silicided contact area.

Claim 2

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure adjacent to an upper surface thereof; (b) forming a diffusion barrier layer over said semiconductor structure, said diffusion barrier layer being patterned such that a first region of said diffusion is exposed at said upper surface of said semiconductor structure, while a second region of said diffusion underlies said diffusion barrier layer; (c) forming a polysilicon layer over said diffusion barrier layer and said first region of said diffusion; (d) diffusing dopant from said first region into said polysilicon layer, thereby forming a doped polysilicon region, wherein said diffusion barrier layer prevents diffusion of said dopant from said diffusion into that portion of said polysilicon layer extending over the diffusion barrier layer, thereby defining an undoped polysilicon region; (e) forming an oxide layer over said doped polysilicon region; and (f) removing said diffusion barrier layer, and siliciding said second region of said diffusion from said upper surface of said semiconductor structure, said second region comprising a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion, wherein said first contact area comprises a first silicided contact area and said second contact area comprises a second silicided contact area, and wherein electrical contact is made to said diffusion resistor structure through said first silicided contact area and said second silicided contact area.

Claim 13

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) after said patterning and removing, growing by thermal oxidation an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; and (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area.

Claim 14

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) after said patterning and removing, growing by thermal oxidation an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; and (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area.

Claim 15

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) forming an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area; and wherein said mask layer comprises a nitride layer and wherein said removing step (e) comprises reactive ion etching said nitride to remove said nitride from the upper surface of said semiconductor structure above said second region of said diffusion.

Claim 16

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) forming an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area; and wherein said mask layer comprises a nitride layer and wherein said removing step (e) comprises reactive ion etching said nitride to remove said nitride from the upper surface of said semiconductor structure above said second region of said diffusion.

Claim 17

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) forming an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area; and wherein said siliciding step (f) comprises depositing and annealing titanium on said second region of said diffusion, thereby forming titanium silicide integral with said second region.

Claim 18

A method for fabricating a diffusion resistor structure, said method comprising the steps of: (a) forming an isolated, resistor-shaped diffusion in a semiconductor structure from an upper surface thereof; (b) forming a mask layer over said diffusion; (c) patterning and removing a portion of said mask layer to expose a first region of said diffusion at said upper surface of said semiconductor structure; (d) forming an oxide layer above said first region of said diffusion; (e) removing said mask layer from overlying a second region of said diffusion, said second region including a first contact area and a second contact area, said first contact area and said second contact area being separated by said first region of said diffusion; (f) siliciding said first contact area and said second contact area of said second region of said diffusion, thereby producing a first silicided contact area and a second silicided contact area, wherein electrical contact is made to said diffusion resistor structure through the first silicided contact area and the second silicided contact area; and wherein said siliciding step (f) comprises depositing and annealing titanium on said second region of said diffusion, thereby forming titanium silicide integral with said second region.