Cluster ion implantation for defect engineering
View Patent ↗A method of semiconductor manufacturing is disclosed in which doping is accomplished by the implantation of ion beams formed from ionized molecules, and more particularly to a method in which molecular and cluster dopant ions are implanted into a substrate with and without a co-implant of non-dopant cluster ion, such as a carbon cluster ion, wherein the dopant ion is implanted into the amorphous layer created by the co-implant in order to reduce defects in the crystalline structure, thus reducing the leakage current and improving performance of the semiconductor junctions. These compounds include co-implants of carbon clusters with implants of monomer or cluster dopants or simply implanting cluster dopants. In particular, the invention described herein consists of a method of implanting semiconductor wafers implanting semiconductor wafers with carbon clusters followed by implants of boron, phosphorus, or arsenic, or followed with implants of dopant clusters of boron, phosphorus, or arsenic.
1. A method of implantation for semiconductor manufacturing, comprising the following steps:
a. creating a flow of C n H m vapor or gas, where n and m are integers such that n>1 and m≧0;
b. introducing said vapor or gas into the ion source of an ion implanter;
c. ionizing said vapor or gas to form ions of C n H x + , where x is a positive integer or zero;
d. accelerating said ions into a n- or p-type silicon substrate at a depth R p ;
e. implanting a dopant ion of the form A n R z H x + to a silicon depth R′ p <R p , defining a doped silicon substrate, where A is either an n- or p-type dopant in silicon, selected from the group of As, P, B, In or Sb, and where R denotes a molecule whose atomic constituents are not injurious to the silicon transistor formation process, selected from the group of Si, Ge, F, or C, and n, x and z are positive integers greater than or equal to zero;
f. activating said doped silicon substrate with a heat treatment to cure defects resulting from said implanting of said dopant ion.
2. The method of claim 1 , where C n H x + is C 16 H x + or C 7 H x + .
3. The method of claim 1 where A n R z H x + is B 18 H x + .
4. The method of claim 1 where A n R z H x + is a carborane.
5. The method of claim 4 where A n R z H x + is C 2 B 10 H x + .
6. The method of claim 1 where A n R z H x + is BF 2 + .
7. The method of claim 1 where A n R z H x + is B.
8. The method of claim 1 where A n R z H x + is B 10 H x + .
9. The method of claim 1 where A n R z H x + is B 20 H x + .
10. The method of claim 1 where A n R z H x + is B 2 H x + .
11. The method of claim 1 where A n R z H x + is B 5 H x + .
12. The method of claim 1 where A n R z H x + is P 7 H x + .
13. The method of claim 1 where A n R z H x + is As 7 H x + .
14. The method of claim 1 where A n R z H x + is (CH 3 ) 5 P 7 + .
15. The method of claim 1 where A n R z H x + is P 7 (SiMe 3 ) 3 + .
16. The method of claim 1 where A n R z H x + is As 7 (SiH 3 ) 3 + .
17. A method of implantation for semiconductor manufacturing, comprising the following steps:
a. creating a flow of A n R z H x vapor or gas, defining a dopant vapor or gas, where A is either an n- or p-type dopant in silicon, selected from the group of As, P, B, In or Sb, and R denoting a molecule whose atomic constituents are not injurious to the silicon transistor formation process, selected from the group of Si, Ge, or C, and n, x and z are positive integers greater than or equal to zero;
b. introducing said dopant vapor or gas into the ion source of an ion implanter;
c. ionizing said vapor or gas to form dopant-containing ions of A b L z H x + where b is a positive integer ≦n, x is a positive integer or zero, and L z contains one or more of the constituents of R z , where z is a positive integer greater than or equal to zero;
d. accelerating said dopant-containing ions into a n- or p-type silicon substrate at a depth R p ′;
e. creating a flow of C k H f vapor or gas, defining a carbon-based vapor or gas, where k and f are integers such that k>1 and f≧0;
f. introducing said carbon based vapor or gas into the ion source of an ion implanter;
g. ionizing said carbon based vapor or gas to form carbon containing ions of C k H x + , where x is a positive integer or zero;
h. accelerating said carbon containing ions onto the said silicon substrate to a depth R p >R p ′;
i. activating the dopant(s) with a heat treatment to cure defects resulting from said implanting of said dopant-containing ions.