ION IMPLANTATION DEVICE AND METHOD OF SEMICONDUCTOR MANUFACTURING BY THE IMPLANTATION OF MOLECULAR IONS CONTAINING PHOSPHORUS AND ARSENIC

摘要

An ion implantation device and a method of manufacturing a semiconductor device is described, wherein ionized phosphorus-containing molecular clusters are implanted to form N-type transistor structures. For example, in the fabrication of Complementary Metal-Oxide Semiconductor (CMOS) devices, the clusters are implanted to provide N-type doping for Source and Drain structures and Pocket or Halo formation, and for counter-doping Poly gates. These doping steps are critical to the formation of NMOS transistors. The molecular cluster ions have the chemical form AnHx<SUP>+</SUP>, or AnRHx<SUP>+</SUP>, where n and x are integers with 4 < n, and x > 0, and A is either As or P, and R is a molecule not containing phosphorus or arsenic, which is not injurious to the implantation process. The use of such phosphorus or arsenic-containing clusters will provide a dramatic increase in wafer throughput, improved device performance, reduced cost per wafer, simplification in transistor formation, improved device yields through the reduction of wafer charging, and other benefits. Thus, this technology significantly reduces manufacturing costs relative to prior implantation techniques. A method of manufacturing a semiconductor device is further described, comprising the steps of: providing a supply of molecules containing a plurality of dopant atoms into an ionization chamber, ionizing said molecules into dopant cluster ions, extracting and accelerating the dopant cluster ions with an electric field, selecting the desired cluster ions 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 molecules contain n dopant atoms, where n is an integer number equal to or greater than 4. This method enables increasing the dopant dose rate to n times the implantation current with an equivalent per dopant atom energy of less than or equal to 1/n times the cluster implantation energy, while reducing the charge per dopant atom by the factor n. This is an effective method for making shallow transistor junctions, where it is desired to implant with a low energy per dopant atom.