Method of manufacturing CMOS devices by the implantation of N- and P-type cluster ions

Abstract

A method of manufacturing a semiconductor device is described, wherein clusters of N- and P-type dopants are implanted to form the transistor structures in CMOS devices. For example, As 4 H x + clusters and either B 10 H x − or B 10 H x + clusters are used as sources of As and B doping, respectively, during the implants. An ion implantation system is described for the implantation of cluster ions into semiconductor substrates for semiconductor device manufacturing. A method of producing higher-order cluster ions of As, P, and B is presented, and a novel electron-impact ion source is described which favors the formation of cluster ions of both positive and negative charge states. The use of cluster ion implantation, and even more so the implantation of negative cluster ions, can significantly reduce or eliminate wafer charging, thus increasing device yields. A method of manufacturing a semiconductor device is further described, comprising the steps of: providing a supply of dopant atoms or molecules into an ionization chamber, combining the dopant atoms or molecules into clusters containing a plurality of dopant atoms, ionizing the dopant clusters into dopant cluster ions, extracting and accelerating the dopant cluster ions with an electric field, selecting the desired cluster ion by mass analysis, modifying the final implant energy of the cluster ion through post-analysis ion optics, and implanting the dopant cluster ions into a semiconductor substrate. In general, dopant clusters contain n dopant atoms where n can be 2, 3, 4 or any integer number. This method provides the advantages of increasing the dopant dose rate to n times the implantation current with an equivalent per dopant atom energy of 1/n times the cluster implantation energy. This is an effective method for making shallow transistor junctions, where it is desired to implant with a low energy per dopant atom.

What is claimed and desired to be covered by a Letters Patent is as follows:  
     
         1 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions As 4 +; and    implanting said N-type As 4 + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         2 . The method as recited in  claim 1 , wherein said generating step comprises: 
 providing a source of arsine (AsH 3 ) gas;    providing a conduit between said source of arsine (AsH 3 ) gas and an ionization chamber to enable said gaseous arsine (AsH 3 ) to communicate with said ionization chamber; and    ionizing said arsine (AsH 3 ) gas in said ionization chamber.    
     
     
         3 . The method as recited in  claim 2 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         4 . The method as recited in  claim 2 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         5 . The method as recited in  claim 2 , wherein said implanting step includes the step of extracting As 4 + ions from said ionization chamber by an electric field.  
     
     
         6 . The method as cited in  claim 5 , further including the step of mass analyzing the extracted ions by selecting the As 4 + ions.  
     
     
         7 . The method as recited in  claim 1 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         8 . The method as recited in  claim 7 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         9 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions As 3   + ; and    implanting said N-type As 3   +  dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         10 . The method as recited in  claim 9 , wherein said generating step comprises: 
 providing a source of arsine (AsH 3 ) gas;    providing a conduit between said source of arsine (AsH 3 ) gas and an ionization chamber to enable said gaseous arsine (AsH 3 ) to communicate with said ionization chamber; and    ionizing said arsine (AsH 3 ) gas in said ionization chamber.    
     
     
         11 . The method as recited in  claim 10 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         12 . The method as recited in  claim 10 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         13 . The method as recited in  claim 10 , wherein said implanting step includes the step of extracting As 3   +  ions from said ionization chamber by an electric field.  
     
     
         14 . The method as cited in  claim 13 , further including the step of mass analyzing the extracted ions by selecting the As 3   +  ions.  
     
     
         15 . The method as recited in  claim 9 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         16 . The method as recited in  claim 15 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         17 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions As 4 H x   + , where x is an integer and 1≦x≦6;    implanting said N-type dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         18 . The method as recited in  claim 17 , wherein said generating step comprises: 
 providing a source of arsine (AsH 3 ) gas;    providing a conduit between said source of arsine (AsH 3 ) gas and an ionization chamber to enable said gaseous arsine (AsH 3 ) to communicate with said ionization chamber; and    ionizing said arsine (AsH 3 ) gas in said ionization chamber.    
     
     
         19 . The method as recited in  claim 18 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         20 . The method as recited in  claim 18 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         21 . The method as recited in  claim 18 , wherein said implanting step includes the step of extracting said dopant cluster ions from said ionization chamber by an electric field.  
     
     
         22 . The method as cited in  claim 21 , further including the step of mass analyzing the extracted ions by selecting said dopant cluster ions.  
     
     
         23 . The method as recited in  claim 17 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         24 . The method as recited in  claim 23 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         25 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions As 3  Hx+, where x is an integer and 1≦x≦5; and    implanting said N-type As 3  Hx+, cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         26 . The method as recited in  claim 25 , wherein said generating step comprises: 
 providing a source of arsine (AsH 3 ) gas;    providing a conduit between said source of arsine (AsH 3 ) gas and an ionization chamber to enable said gaseous arsine (AsH 3 ) to communicate with said ionization chamber; and    ionizing said arsine (AsH 3 ) gas in said ionization chamber.    
     
     
         27 . The method as recited in  claim 26 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         28 . The method as recited in  claim 26 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         29 . The method as recited in  claim 26 , wherein said implanting step includes the step of extracting said dopant cluster ions from said ionization chamber by an electric field.  
     
     
         30 . The method as cited in  claim 29 , further including the step of mass analyzing the extracted ions and selecting the As 3 H x + species.  
     
     
         31 . The method as recited in  claim 23 , further including the step of: 
 generating P-type dopant cluster ions, and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         32 . The method as recited in  claim 31 , wherein said generating step comprises generating negative decaborane cluster ion (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         33 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions P 4 +; and    implanting said N-type P 4 + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         34 . The method as recited in  claim 33 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phosphine (PH 3 ) gas and an ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         35 . The method as recited in  claim 34 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         36 . The method as recited in  claim 34 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         37 . The method as recited in  claim 34 , wherein said implanting step includes the step of extracting P 4 + ions from said ionization chamber by an electric field.  
     
     
         38 . The method as cited in  claim 37 , further including the step of mass analyzing the extracted ions by selecting the P 4 + species.  
     
     
         39 . The method as recited in  claim 33 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         40 . The method as recited in  claim 39 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         41 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions P 3 +; and    implanting said N-type P 3 + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         42 . The method as recited in  claim 41 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phospine (PH 3 ) gas and an ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         43 . The method as recited in  claim 42 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         44 . The method as recited in  claim 47 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         45 . The method as recited in  claim 42 , wherein said implanting step includes the step of extracting P 3 + ions from said ionization chamber.  
     
     
         46 . The method as cited in  claim 50 , further including the step of mass analyzing the extracted ions by selecting the P 3 + species.  
     
     
         47 . The method as recited in  claim 42  further including the step of: 
 generating P-type dopant cluster ions; and  
 implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.  
 
     
     
         48 . The method as recited in  claim 47 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         49 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type dopant cluster ions P 2 +; and    implanting said N-type P 2 + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         50 . The method as recited in  claim 49 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phosphine (PH 3 ) gas and an ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         51 . The method as recited in  claim 50 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         52 . The method as recited in  claim 50 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         53 . The method as recited in  claim 50 , wherein said implanting step includes the step of extracting P 2 + ions from said ionization chamber by an electric field.  
     
     
         54 . The method as recited in  claim 50 , further including the step of mass analyzing the extracted ions by selecting the P 2 + species.  
     
     
         55 . The method as recited in  claim 50 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         56 . The method as recited in  claim 55 , wherein said generating step comprises generating negative decaborane cluster ion (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         57 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type cluster dopant ions P 4 H x +, where x is an integer and 1≦x≦6; and    implanting said N-type P 4 H x + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         58 . The method as recited in  claim 57 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phosphine (PH 3 ) gas and an ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         59 . The method as recited in  claim 58 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         60 . The method as recited in  claim 58 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         61 . The method as recited in  claim 58 , wherein said implanting step includes the step of extracting P 4 H x + ions from said ionization chamber by an electric field, where x is an integer and 1≦x≦6.  
     
     
         62 . The method as cited in  claim 61 , further including the step of mass analyzing the extracted ions by selecting said dopant cluster ions.  
     
     
         63 . The method as recited in  claim 57 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         64 . The method as recited in  claim 63 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         65 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating N-type cluster dopant ions P 3 H x +, where x is an integer and 1≦x≦5; and    implanting said N-type P 3 H x + dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         66 . The method as recited in  claim 65 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phosphine (PH 3 ) gas and an ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         67 . The method as recited in  claim 66 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         68 . The method as recited in  claim 66 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         69 . The method as recited in  claim 66 , wherein said implanting step includes the step of extracting said dopant cluster ions from said ionization chamber by an electric field.  
     
     
         70 . The method as cited in  claim 66 , further including the step of mass analyzing the extracted ions and selecting said dopant cluster ions.  
     
     
         71 . The method as recited in  claim 65 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         72 . The method as recited in  claim 71 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         73 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating an N-type cluster dopant ions P 2 H x +, where x is an integer and 1≦x≦4 and    implanting said N-type P 2 H x +, dopant cluster ions into a first region of said substrate resulting in N-type doping of said substrate.    
     
     
         74 . The method as recited in  claim 73 , wherein said generating step comprises: 
 providing a source of phosphine (PH 3 ) gas;    providing a conduit between said source of phosphine (PH 3 ) gas and said ionization chamber to enable said gaseous phosphine (PH 3 ) to communicate with said ionization chamber; and    ionizing said phosphine (PH 3 ) gas in said ionization chamber.    
     
     
         75 . The method as recited in  claim 73 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         76 . The method as recited in  claim 73 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         77 . The method as recited in  claim 73 , wherein said implanting step includes the step of extracting said dopant ions from said ionization chamber by an electric field.  
     
     
         78 . The method as cited in  claim 77 , further including the step of mass analyzing the extracted cluster ions and selecting the P 2 H x + species, where x is an integer and 1≦x≦4.  
     
     
         79 . The method as recited in  claim 73 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         80 . The method as recited in  claim 79 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ), where x is an integer and 0≦x≦14.  
     
     
         81 . A method of implanting a cluster ion dopant material into a semiconductor substrate comprising the steps of: 
 generating a dopant ion cluster, B n H x +, where n and x are integers and 2≦n≦9 and 0≦x≦14; and    implanting said dopant ion cluster into a first region of said substrate.    
     
     
         82 . The method as recited in  claim 81 , wherein said generating step comprises: 
 providing a source of diborone (B 2 H 6 ) gas;    providing a conduit between said source of diborone (B 2 H 6 ) gas and an ionization chamber to enable said diborone (B 2 H 6 ) gas to communicate with said ionization chamber; and    ionizing said diborone (B 2 H 6 ) gas in said ionization chamber.    
     
     
         83 . The method as recited in  claim 82 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         84 . The method as recited in  claim 82 , further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         85 . The method as recited in  claim 82 , wherein said implanting step includes the step of extracting said dopant cluster ions from said ionization chamber by an electric field  
     
     
         86 . The method as cited in  claim 95 , further including the step of mass analyzing the extracted ions by selecting said dopant cluster ions.  
     
     
         87 . The method as recited in  claim 81 , further including the step of: 
 generating P-type dopant cluster ions; and    implanting said P-type dopant cluster ions into said substrate into a second region different than said first region.    
     
     
         88 . The method as recited in  claim 87 , wherein said generating step comprises generating negative decaborane cluster ions (B 10 H x   − ) where x is an integer and 0≦x≦14.  
     
     
         89 . A method of implanting dopant materials into a semiconductor substrate comprising: 
 generating P-type negative decaborane cluster dopant ions (B 10 H x   − ), where x is an integer and 0≦x≦14; and    implanting said negative decaborane (B 10 H x   − ) dopant cluster ions into a first region on said substrate resulting in P-type doping of said substrate.    
     
     
         90 . The method as recited in  claim 88 , wherein said generating step comprises: 
 providing a source of decaborane (B 10 H 14 ) vapor;    providing a conduit between said source of decaborane (B 10 H 14 ) vapor and an ionization chamber to enable said decaborane (B 10 H 14 ) vapor to communicate with said ionization chamber; and    ionizing said decaborane (B 10 H 14 ) vapor in said ionization chamber.    
     
     
         91 . The method as recited in  claim 90 , wherein said ionizing step comprises irradiation within said ionization chamber by one or more electron beams.  
     
     
         92 . The method as recited in  claim 90 , wherein further including the step of controlling the temperature of said ionization chamber to a predetermined value.  
     
     
         93 . The method as recited in  claim 90 , wherein said implanting step includes the step of extracting negative decaborane cluster ions B 10 H x   −  from said ionization chamber, where x is an integer and 0≦x≦14.  
     
     
         94 . The method as recited in  claim 93 , further including the step of mass analyzing negative decaborane cluster ions B 10 H x   − , species where x equals 0≦x≦14.  
     
     
         95 . A semiconductor device comprising: 
 a substrate having one or more N-type regions formed from an N-type material; and    a P-type dopant implanted into said N-type region, said P-type dopant formed by implantation of negative decaborane cluster ions B 10 H x   −  into said p-type region, where x is an integer and 0≦x≦14.    
     
     
         96 . The method as recited in  claim 8 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         97 . The method as recited in  claim 17 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         98 . The method as recited in  claim 26 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         99 . The method as recited in  claim 35 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         100 . The method as recited in  claim 44 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         101 . The method as recited in  claim 53 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         102 . The method as recited in  claim 62 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         103 . The method as recited in  claim 71 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         104 . The method as recited in  claim 80 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         105 . The method as recited in  claim 89 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         106 . The method as recited in  claim 98 , wherein said generating step comprises generating positive decaborane (B 10 H x +) cluster ions, where 0≦x≦14.  
     
     
         107 . A method of forming cluster ions comprising: 
 providing a supply of dopant atoms into an ionization chamber; and    combining the dopant atoms into clusters containing a plurality of dopant atoms.    
     
     
         108 . The method as recited in  claim 107  further comprising: 
 ionizing the dopant clusters into dopant cluster ions;  
 extracting said dopant cluster ions; and  
 implanting said dopant cluster ions into a substrate.  
 
     
     
         109 . The method as recited in  claim 107 , wherein said supply of dopant atoms is in the form of A s H 3 .  
     
     
         110 . The method as recited in  claim 109 , wherein said supply of dopant atoms is in the form of PH 3 .  
     
     
         111 . The method as recited in  claim 109 , wherein said supply of dopant atoms is in the form of B 2 H 6 .  
     
     
         112 . A method of forming cluster ions comprising: 
 providing a supply of dopant molecules into an ionization chamber; and    combining the dopant molecules into clusters containing a plurality of dopant molecules.    
     
     
         113 . The method as recited in  claim 112  further comprising: 
 ionizing the dopant clusters into dopant cluster ions;  
 extracting said dopant cluster ions; and  
 implanting said dopant cluster ions into a substrate.  
 
     
     
         114 . The method as recited in  claim 113 , wherein said supply of dopant atoms is in the form of A s H 3 .  
     
     
         115 . The method as recited in  claim 113 , wherein said supply of dopant atoms is in the form of PH 3 .  
     
     
         116 . The method as recited in  claim 113 , wherein said supply of dopant atoms is in the form of B 2 H 6 .  
     
     
         117 . The method as recited in  claim 81 , wherein said generating step comprises: 
 providing a source of decaborane (B 10 H 14 ) vapor;    providing a conduit between said source of decaborane (B 10 H 14 ) vapor and an ionization chamber to enable said gas to communicate with said ionization chamber; and    ionizing said decaborane (B 10 H 14 ) vapor in said ionization chamber.