Method of making a metal oxide semiconductor (MOS) transistor polysilicon gate with a size beyond photolithography limitation by using polysilicidation and selective etching
First Claim
Patent Images
1. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
- (a) providing a polysilicon gate on a gate oxide layer, the polysilicon gate having a top and a sidewall;
(b) forming a conformal layer of a metal on the polysilicon gate and the gate oxide layer;
(c) removing a portion of the conformal layer to leave a spacer layer of the metal on the sidewall of the polysilicon gate;
(d) forming a metal silicide sidewall surrounding the polysilicon gate by silicidizing the metal spacer layer with the polysilicon; and
(e) removing the metal silicide sidewall from the polysilicon gate, thereby reducing the size of the polysilicon gate.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of fabricating a polysilicon gate 8 in a metal oxide semiconductor (MOS) transistor in an integrated circuit includes providing a metal layer 18, such as cobalt, on the sidewall 12 of the polysilicon gate 8, silicidizing the metal with the polysilicon in the polysilicon gate 8 to form a metal silicide sidewall 20, and removing the metal silicide sidewall 20 by etching.
37 Citations
58 Claims
-
1. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) providing a polysilicon gate on a gate oxide layer, the polysilicon gate having a top and a sidewall; (b) forming a conformal layer of a metal on the polysilicon gate and the gate oxide layer; (c) removing a portion of the conformal layer to leave a spacer layer of the metal on the sidewall of the polysilicon gate; (d) forming a metal silicide sidewall surrounding the polysilicon gate by silicidizing the metal spacer layer with the polysilicon; and (e) removing the metal silicide sidewall from the polysilicon gate, thereby reducing the size of the polysilicon gate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) patterning and etching a polysilicon layer on a gate oxide layer to form a polysilicon gate having a top and a sidewall; (b) providing a cap layer on the top of the polysilicon gate; (c) depositing a conformal layer of a metal on the polysilicon gate, the gate oxide layer and the cap layer; (d) etching the conformal layer to leave a spacer layer of the metal on the sidewall of the polysilicon gate; (e) silicidizing the metal spacer layer with the polysilicon to form a metal silicide sidewall surrounding the polysilicon gate; (f) removing the cap layer; and (g) etching the metal silicide sidewall to remove the metal silicide from the polysilicon gate, thereby reducing the size of the polysilicon gate. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) patterning and etching a polysilicon layer on a gate oxide layer to form a polysilicon gate having a top and a sidewall; (b) depositing a conformal layer of cobalt (Co) on the polysilicon gate and the gate oxide layer; (c) etching the conformal layer to leave a spacer layer of Co on the sidewall of the polysilicon gate; (d) silicidizing the Co spacer layer with the polysilicon at a low silicidation temperature to form a cobalt disilicide (CoSi2) sidewall surrounding the polysilicon gate; and (e) etching the CoSi2 sidewall to remove the CoSi2 from the polysilicon gate, thereby reducing the size of the polysilicon gate. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
-
-
46. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) patterning and etching a polysilicon layer on a gate oxide layer to form a polysilicon gate having a top and a sidewall; (b) providing a silicon nitride oxide (SiON) cap layer on the top of the polysilicon gate; (c) depositing a conformal layer of cobalt (Co) on the polysilicon gate, the gate oxide layer and the SiON cap layer; (d) etching the conformal layer to leave a spacer layer of Co on the sidewall of the polysilicon gate; (e) silicidizing the Co spacer layer with the polysilicon at a low silicidation temperature to form a cobalt disilicide (CoSi2) sidewall surrounding the polysilicon gate; (f) removing the SiON cap layer; and (g) etching the CoSi2 sidewall to remove the CoSi2 from the polysilicon gate, thereby reducing the size of the polysilicon gate. - View Dependent Claims (47, 48, 49, 50, 51, 52)
-
-
53. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) patterning and etching a polysilicon layer on a gate oxide layer to form a polysilicon gate having a top and a sidewall; (b) depositing a conformal layer of cobalt (Co) on the polysilicon gate and the gate oxide layer by chemical vapor deposition (CVD); (c) reactive ion etching the conformal layer with an anisotropic etch to leave a spacer layer of Co on the sidewall of the polysilicon gate; (d) silicidizing the Co spacer layer with the polysilicon at a temperature of about 600°
C. to form a cobalt disilicide (CoSi2) sidewall surrounding the polysilicon gate; and(e) etching the CoSi2 sidewall with hydrochloric acid (HCl) to remove the CoSi2 from the polysilicon gate, thereby reducing the size of the polysilicon gate. - View Dependent Claims (54, 55, 56, 57)
-
-
58. A method of fabricating a polysilicon gate of a metal oxide semiconductor (MOS) transistor, comprising the steps of:
-
(a) patterning and etching a polysilicon layer on a gate oxide layer to form a polysilicon gate having a top and a sidewall; (b) providing a silicon nitride oxide (SiON) cap layer on the top of the polysilicon gate; (c) depositing a conformal layer of cobalt (Co) on the polysilicon gate, the gate oxide layer and the SiON cap layer by chemical vapor deposition (CVD); (d) reactive ion etching the conformal layer with an anisotropic etch using the SiON cap layer as an etch stop to leave a spacer layer of Co on the sidewall of the polysilicon gate; (e) silicidizing the Co spacer layer with the polysilicon at a temperature of about 600°
C. to form a cobalt disilicide (CoSi2) sidewall surrounding the polysilicon gate;(f) etching the SiON cap layer with sulfuric acid (H2 SO4) to remove the SiON cap layer from the polysilicon gate; and (g) etching the CoSi2 sidewall with boiling concentrated hydrochloric acid (HCl) to remove the CoSi2 from the polysilicon gate, thereby reducing the size of the polysilicon gate.
-
Specification