- published: 12 Jun 2012
- views: 17112
Ion implantation is a materials engineering process by which ions of a material are accelerated in an electrical field and impacted into a solid. This process is used to change the physical, chemical, or electrical properties of the solid. Ion implantation is used in semiconductor device fabrication and in metal finishing, as well as various applications in materials science research. The ions alter the elemental composition of the target (if the ions differ in composition from the target), stopping in the target and staying there. They also cause many chemical and physical changes in the target by transferring their energy and momentum to the electrons and atomic nuclei of the target material. This causes a structural change, in that the crystal structure of the target can be damaged or even destroyed by the energetic collision cascades. Because the ions have masses comparable to those of the target atoms, they knock the target atoms out of place more than electron beams do. If the ion energy is sufficiently high (usually tens of MeV) to overcome the coulomb barrier, there can even be a small amount of nuclear transmutation.
Ion implantation is one of the fundamental processes used to make microchips. Raw silicon is neither a perfect insulator nor a perfect conductor. It's somewhere in the middle. Inserting a smattering of boron or phosphorus atoms into the silicon crystal lattice allows us to control the flow of electricity through the silicon and make transistors -- the building block from which we make chips. In this two-part video features Jim Kawski from Applied's Varian Semiconductor Equipment business unit, discussing why we need ion implantation, what the process looks like at the atomic level and how an actual implanter works. In the second part, Jim goes on to explore how implant is used to make actual semiconductor devices.
Ion Implantation, part 1
Processing of Semiconducting Materials by Dr. Pallab Banerji,Department of Metallurgy and Material Science,IIT Kharagpur.For more details on NPTEL visit http://nptel.ac.in
"Plasma-immersion ion implantation" or pulsed-plasma doping is a surface modification technique of extracting the accelerated ions from the plasma by applying a high voltage pulsed DC or pure DC power supply and targeting them into a suitable substrate or electrode with a semiconductor wafer placed over it, so as to implant it with suitable dopants. The electrode is a cathode for an electropositive plasma, while it is an anode for an electronegative plasma. Plasma can be generated in a suitably designed vacuum chamber with the help of various plasma sources such as Electron Cyclotron Resonance plasma source which yields plasma with the highest ion density and lowest contamination level, helicon plasma source, capacitively coupled plasma source, inductively coupled plasma source, DC g...