Ion implantation device and a method of semiconductor manufacturing by the implantation of boron hydride cluster ions
View Patent ↗An ion implantation device and a method of manufacturing a semiconductor device is described, wherein ionized boron hydride molecular clusters are implanted to form P-type transistor structures. For example, in the fabrication of Complementary Metal-Oxide Semiconductor (CMOS) devices, the clusters are implanted to provide P-type doping for Source and Drain structures and for Polygates; these doping steps are critical to the formation of PMOS transistors. The molecular cluster ions have the chemical form B n H x + and B n H x − where 10<n<100 and 0<x<n+4.
1. A method of implanting ions comprising the steps of:
(a) producing a volume of gas phase molecules which include boron hydride B n H m molecules, where n and m are integers and n>10 and m≧0 defining a molecular structure;
(b) ionizing said molecular structure defining an ionized molecular structure; and
(c) accelerating said ionized molecular structure by an electric field into a target.
2. The method as recited in claim 1 , in which step (a) comprises producing a volume or gas phase molecules of octadecaborane, B 18 H 22 .
3. The method as recited in claim 2 , in which step (c) comprises accelerating molecules of B 18 H x + , where 0≦x≦22.
4. The method as recited in claim 2 , in which step (c) comprises accelerating molecules of B 18 H x − , where 0≦x≦22.
5. The method as recited in claim 1 , in which step (a) comprises producing a volume of gas by sublimation of a solid by heating above 20° C.
6. The method as recited in claim 1 , wherein said step (c) comprises accelerating said boron hydride ions into a silicon target.
7. The method as recited in claim 1 , wherein step (c) comprises accelerating boron hydride ions into a silicon-on-insulator substrate target.
8. The method as recited in claim 1 , wherein step (c) comprises accelerating boron hydride ions into a strained superlattice substrate target.
9. The method as recited in claim 1 , wherein step (c) comprises accelerating boron hydride ions into a substrate a silicon germanium (SiGe) strained superlattice target.
10. A method of implanting ions comprising the steps of:
(a) producing a volume of gas phase molecules which include molecules of boron hydride B n H m molecules where n and m are integers and n>10 and m≧0 defining a molecular structure;
(b) forming a plasma containing said molecular structure, molecular ions and electrons; and
(c) accelerating the molecular ions by an electric field to implant into a target, to perform doping of a semiconductor.
11. The method of claim 10 , wherein said electric field is a time-varying or pulsed electric field.
12. The method of claim 10 , wherein said electric field is a constant or DC electric field.
13. The method as recited in claim 10 , in which step (a) comprises producing octadecaborane vapor, B 18 H 22 .
14. The method as recited in claim 10 , in which step (b) comprises forming a plasma of B 18 H x + ions, where 0≦x≦22.
15. The method as recited in claim 10 , in which step (a) comprises producing a volume of gas by sublimation of a solid by heating above 20 C.
16. The method as recited in claim 10 , wherein step (c) comprises accelerating said boron hydride ions into a silicon target.
17. The method as recited in claim 10 , wherein step (c) comprises accelerating said boron hydride ions into a silicon-on-insulator substrate target.
18. The method as recited in claim 10 , wherein step (c) comprises accelerating said boron hydride ions into a strained superlattice substrate target.
19. The method as recited in claim 10 , wherein step (c) comprises accelerating said boron hydride ions into a silicon germanium (SiGe) strained superlattice target.
20. The method as recited in claim 1 , wherein Step (b) comprises:
(b) ionizing said molecular structure by direct electron impact.