Method of composite gate formation

Abstract

Methods for forming a nitride barrier film layer in semiconductor devices such as gate structures, and barrier layers, semiconductor devices and gate electrodes are provided. The nitride layer is particularly useful as a barrier to boron diffusion into an oxide film. The nitride barrier layer is formed by selectively depositing silicon onto an oxide substrate as a thin layer, and then thermally annealing the silicon layer in a nitrogen-containing species or exposing the silicon to a plasma source of nitrogen to nitridize the silicon layer.

What is claimed is:  
     
         1 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a dielectric layer to a silicon-containing species under low partial pressure to deposit a layer of silicon thereon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         2 . The method of  claim 1 , wherein the dielectric layer is exposed to the silicon-containing species at a partial pressure of about 10 −2  Torr or less.  
     
     
         3 . The method of  claim 1 , wherein the dielectric layer is exposed to the silicon-containing species at pressure of about 10 −2  to about 10 −7  Torr.  
     
     
         4 . The method of  claim 2 , wherein the dielectric layer is exposed to the silicon-containing species at a temperature of about 500° C. to about 700° C.  
     
     
         5 . A method of forming a nitride barrier layer, comprising the steps of: 
 irradiating a dielectric layer with a silicon-containing species under low partial pressure to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         6 . The method of  claim 5 , wherein the silicon layer has a thickness of about 10 to about 30 angstroms.  
     
     
         7 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a dielectric layer to a silicon-containing species under low partial pressure to deposit a layer of about 10 to about 30 angstroms silicon thereon; and    nitridizing the silicon layer in a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         8 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a surface of a dielectric layer to a silicon-containing species at a low partial pressure to nucleate the surface of the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         9 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less to deposit a layer of about 10 to about 30 angstroms silicon thereon; and    nitridizing the silicon layer to form a silicon nitride barrier layer.    
     
     
         10 . The method of  claim 9 , wherein the dielectric layer is exposed to the silicon-containing species at a temperature of about 500° C. to about 700° C.  
     
     
         11 . The method of  claim 9 , wherein the silicon-containing species is selected from the group consisting of dichlorosilane, silicon tetrachloride, silane, and disilane.  
     
     
         12 . The method of  claim 9 , wherein the step of exposing the dielectric layer to the silicon-containing species is by plasma enhanced chemical vapor deposition, low pressure chemical vapor deposition, or rapid thermal chemical vapor deposition.  
     
     
         13 . The method of  claim 9 , wherein the silicon-containing species is deposited by rapid thermal chemical vapor deposition at about 500° C. to about 700° C.  
     
     
         14 . The method of  claim 9 , wherein the dielectric layer comprises silicon dioxide.  
     
     
         15 . The method of  claim 9 , wherein the dielectric layer comprises a dielectric material selected from the group consisting of tantalum pentoxide, hafnium dioxide, and aluminum trioxide.  
     
     
         16 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  to about 10 −7  to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         17 . A method of forming a nitride barrier layer, comprising the steps of: 
 exposing a dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  to about 10 −7 , a temperature of about 500° C. to about 700° C., and a duration of about 1 second to about 5 minutes, to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         18 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    thermally annealing the silicon layer in a nitrogen-containing species.    
     
     
         19 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a nitrogen-containing species at a temperature of about 700° C. to about 900° C. to nitridize the silicon layer.    
     
     
         20 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a nitrogen-containing species at a temperature of about 700° C. to about 900° C., a pressure of about 1 to about 760 Torr, and a flow rate of about 100 to about 10,000 sccm, for about 1 second to about 180 minutes to nitridize the silicon layer.    
     
     
         21 . The method of  claim 20 , wherein the nitrogen-containing species is selected from the group consisting of nitrogen, ammonia, nitrogen trifluoride, nitrogen oxide, and a nitrogen-helium mixture.  
     
     
         22 . The method of  claim 21 , wherein the silicon layer is exposed to a plasma source of nitrogen.  
     
     
         23 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a plasma source of a nitrogen-containing species to nitridize the silicon layer.    
     
     
         24 . The method of  claim 23 , wherein the plasma source of the nitrogen-containing species is produced by a downstream microwave system, an electron cyclotron residence system, an inductive coupled plasma system, or a radio frequency system.  
     
     
         25 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a remote microwave plasma source of a nitrogen-containing species at a pressure of about 1 to about 20 Torr to nitridize the silicon layer.    
     
     
         26 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a remote microwave plasma source of a nitrogen-containing species at a pressure of about 1 to about 20 Torr, and a temperature of about 700° C. to about 900° C. to nitridize the silicon layer.    
     
     
         27 . A method of forming a nitride barrier layer, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to an inductive coupled plasma source of a nitrogen-containing species at a pressure of about 1 to about 20 Torr to nitridize the silicon layer.    
     
     
         28 . A method of forming a semiconductor device, comprising the steps of: 
 irradiating a dielectric layer disposed on a silicon substrate with a silicon-containing species under low partial pressure to nucleate the dielectric layer with a layer of silicon; and    nitridizing the silicon layer.    
     
     
         29 . The method of  claim 28 , wherein the step of irradiating the dielectric layer with the silicon-containing species is at a partial pressure about 10 −2  Torr or less.  
     
     
         30 . The method of  claim 29 , wherein the step of irradiating the dielectric layer is at a partial pressure of about 10 −2  to about 10 −7  Torr.  
     
     
         31 . The method of  claim 29 , wherein the silicon-containing species is selected from the group consisting of dichlorosilane, silicon tetrachloride, silane, and disilane.  
     
     
         32 . The method of  claim 28 , wherein the step of irradiating the dielectric layer with the silicon-containing species is by plasma enhanced chemical vapor deposition, low pressure chemical vapor deposition, or rapid thermal chemical vapor deposition.  
     
     
         33 . The method of  claim 28 , wherein the step of irradiating the dielectric layer with the silicon-containing species is by rapid thermal chemical vapor deposition at a temperature of about 500° C. to about 700° C.  
     
     
         34 . The method of  claim 28 , wherein the dielectric layer comprises silicon dioxide.  
     
     
         35 . The method of  claim 28 , wherein the dielectric layer comprises a dielectric material selected from the group consisting of tantalum pentoxide, hafnium dioxide, and aluminum trioxide.  
     
     
         36 . A method of forming a semiconductor device, comprising the steps of: 
 exposing a dielectric layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  Torr or less to nucleate the dielectric layer with a layer of silicon; and    nitridizing the silicon layer in a nitrogen-containing species.    
     
     
         37 . A method of forming a semiconductor device, comprising the steps of: 
 exposing an oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  Torr or less to nucleate the dielectric layer with a layer of silicon; and    thermally annealing the silicon layer in a nitrogen-containing gas.    
     
     
         38 . A method of forming a semiconductor device, comprising the steps of: 
 exposing an oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  Torr or less to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species at a temperature of about 700° C. to about 900° C. to nitridize the silicon layer.    
     
     
         39 . A method of forming a semiconductor device, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low partial pressure to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a plasma source of a nitrogen-containing species to nitridize the silicon layer.    
     
     
         40 . The method of  claim 39 , wherein the plasma source of the nitrogen-containing species is produced by a downstream microwave system, an electron cyclotron residence system, an inductive coupled plasma system, or a radio frequency system.  
     
     
         41 . A method of forming a semiconductor device, comprising the steps of: 
 depositing a silicon layer onto a dielectric layer by exposing the dielectric layer to a silicon-containing species under low a partial pressure of about 10 −2  Torr or less to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a remote microwave plasma source of a nitrogen-containing species at a pressure of about 1 to about 20 Torr to nitridize the silicon layer.    
     
     
         42 . A method of forming a gate electrode, comprising the steps of: 
 exposing a gate oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  Torr or less to nucleate the dielectric layer with a layer silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         43 . A method of forming a gate electrode, comprising the steps of: 
 exposing a gate oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  to about 10 −7  to nucleate the dielectric layer with a layer of silicon; and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         44 . A method of forming a gate electrode, comprising the steps of: 
 exposing a gate oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  to about 10 −7 , a temperature of about 500° C. to about 700° C., and a duration of about 1 second to about 5 minutes, to nucleate the dielectric layer with a layer of silicon and    exposing the silicon layer to a nitrogen-containing species to form a silicon nitride barrier layer.    
     
     
         45 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the gate oxide layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less; and    thermally annealing the silicon layer in a nitrogen-containing species.    
     
     
         46 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the gate oxide layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less; and    exposing the silicon layer to a nitrogen-containing species at a temperature of about 700° C. to about 900° C. to nitridize the silicon layer to a silicon nitride layer.    
     
     
         47 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the dielectric layer to a silicon-containing species under low partial pressure; and    exposing the silicon layer to a nitrogen-containing species at a temperature of about 700° C. to about 900° C., a pressure of about 1 to about 760 Torr, a flow rate of about 100 to about 10,000 sccm, for about 1 second to about 180 minutes to nitridize the silicon layer.    
     
     
         48 . The method of  claim 47 , wherein the nitrogen-containing species is selected from the group consisting of nitrogen, ammonia, nitrogen trifluoride, nitrogen oxide, and a mixture of nitrogen and helium.  
     
     
         49 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less; and    exposing the silicon layer to a plasma source of a nitrogen-containing species to nitridize the silicon layer.    
     
     
         50 . The method of  claim 49 , wherein the plasma source of the nitrogen-containing species is produced by a downstream microwave system, an electron cyclotron residence system, an inductive coupled plasma system, or a radio frequency system.  
     
     
         51 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less; and    exposing the silicon layer to a remote microwave plasma source of a nitrogen-containing species at a temperature of about 700° C. to about 900° C., and a pressure of about 1 to about 20 Torr to nitridize the silicon layer.    
     
     
         52 . A method of forming a gate electrode, comprising the steps of: 
 depositing a silicon layer onto a gate oxide layer disposed on a silicon substrate by exposing the dielectric layer to a silicon-containing species at a partial pressure of about 10 −2  Torr or less; and    exposing the silicon layer to an inductive coupled plasma source of a nitrogen-containing species at a pressure of about 1 to about 20 Torr to nitridize the silicon layer.    
     
     
         53 . A method of forming a gate electrode, comprising the steps of: 
 exposing a gate oxide layer disposed on a silicon substrate to a silicon-containing species at a partial pressure of about 10 −2  to about 10 −7  to nucleate the dielectric layer with a layer of silicon;    nitridizing the silicon layer in a nitrogen-containing species to form a silicon nitride barrier layer; and    forming a conductive polysilicon layer comprising a conductivity enhancing dopant over the nitride barrier layer; wherein the nitride barrier layer inhibits passage of the dopant from the conductive polysilicon layer therethrough.    
     
     
         54 . The method of  claim 53 , wherein the polysilicon layer comprises a boron dopant.  
     
     
         55 . The method of  claim 53 , further comprising: 
 forming an insulative nitride cap over the conductive polysilicon layer; and    patterning the layers to form a gate stack.    
     
     
         56 . The method of  claim 53 , further comprising: 
 forming a barrier layer over the doped polysilicon layer;    forming a conductive metal layer over the barrier layer;    forming an insulative nitride cap over the conductive metal layer; and    patterning the layers to form a gate stack.    
     
     
         57 . The method of  claim 53 , further comprising: 
 forming a metal silicide layer over the doped polysilicon layer;    forming an insulative nitride cap over the metal silicide layer; and    patterning the layers to form a gate stack.    
     
     
         58 . A nitride barrier layer, comprising: 
 a nitridized silicon layer of less than about 30 angstroms disposed on an oxide layer, and formed by irradiation of the oxide layer with a silicon-containing species under low partial pressure in the presence of a nitrogen-containing species.    
     
     
         59 . A nitride barrier layer, comprising: a nitridized silicon layer having a thickness of less than about 30 angstroms, and disposed adjacent an oxide layer.  
     
     
         60 . A nitride barrier layer, comprising: an annealed nitridized silicon layer having a thickness of less than about 30 angstroms, and disposed adjacent an oxide layer.  
     
     
         61 . The barrier layer of  claim 60 , wherein the barrier layer is thermally annealed.  
     
     
         62 . The barrier layer of  claim 60 , wherein the barrier layer is plasma annealed.  
     
     
         63 . A semiconductor device comprising: 
 a semiconductor substrate comprising silicon;    an oxide layer disposed adjacent to the semiconductor substrate; and    a diffusion barrier layer disposed adjacent the oxide layer; the diffusion barrier layer having a thickness of less than about 30 angstroms, and comprising a nitridized silicon layer formed by irradiation of an oxide layer with a silicon-containing species under low partial pressure in the presence of a nitrogen-containing species,    
     
     
         64 . A semiconductor device comprising: 
 a semiconductor substrate comprising silicon;    an oxide layer disposed adjacent to the semiconductor substrate; and    a diffusion barrier layer disposed adjacent the oxide layer, and comprising nitridized silicon having a thickness of about 10 to about 20 angstroms.    
     
     
         65 . A semiconductor device comprising: 
 a semiconductor substrate comprising silicon;    an oxide layer disposed adjacent to the semiconductor substrate; and    a diffusion barrier layer disposed adjacent the oxide layer, and comprising nitrogen annealed silicon and having a thickness of about 10 to about 20 angstroms.    
     
     
         66 . The device of  claim 65 , wherein the diffusion barrier layer comprises plasma annealed silicon.  
     
     
         67 . The device of  claim 65 , wherein the diffusion barrier layer comprises thermally annealed silicon.  
     
     
         68 . A gate electrode, comprising: 
 a gate oxide layer disposed adjacent to a semiconductor substrate; and    a diffusion barrier layer disposed adjacent the gate oxide layer; the diffusion barrier layer having a thickness of about 10 to about 20 angstroms and comprising a nitridized silicon layer deposited by irradiating an oxide layer with a silicon-containing species under low partial pressure, and nitridizing the silicon layer by exposure to a nitrogen-containing species.    
     
     
         69 . A gate electrode, comprising: 
 a gate oxide layer disposed adjacent to a semiconductor substrate; and    a diffusion barrier layer disposed adjacent the oxide layer, and comprising a nitridized silicon layer having a thickness of about 10 to about 20 angstroms.    
     
     
         70 . A gate electrode, comprising: 
 a gate oxide layer disposed adjacent to a semiconductor substrate; and    a diffusion barrier layer disposed adjacent the oxide layer, and comprising nitrogen annealed silicon and having a thickness of about 10 to about 20 angstroms.    
     
     
         71 . The electrode of  claim 70 , wherein the diffusion barrier layer comprises plasma annealed silicon.  
     
     
         72 . The electrode of  claim 70 , wherein the diffusion barrier layer comprises thermally annealed silicon.