| 摘要 |
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, As4Hx<+> clusters and either B10Hx<-> or B10Hx<+> 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.
|
