Ion Implantation and Synthesis of Materials - Studium

2 1 General Features and Fundamental ConceptsIon SourceIon AccelerationMassSeparationBeamSweepingTarget ChamberFig. 1.1. Schematic drawing of an ion implantation system. A mass-separating magnet isused to select the ion species (elements and isotopes) of interest. Beam-sweeping facilitiesare required for large-area uniform implantations1.2 Range DistributionsOne of the most important considerations in any description of ion–solidinteractions is the depth (range) distribution of the implanted ions. A large amountof experimental and theoretical work has been devoted to the task of understandingthe energy-loss processes that govern the range distribution, and it is nowpossible to predict fairly accurately most of the factors involved. For example, atypical range distribution in an amorphous substrate from monoenergetic ions atmoderate ion doses is approximately Gaussian in shape and may therefore becharacterized by a projected range, R p , and a straggling, ∆R p , about this meanvalue, as depicted in Fig. 1.2. The notation uses Z and M for atomic number andatomic mass, respectively, with subscript 1 denoting the incident ions (Z 1 , M 1 ) andsubscript 2 denoting the ion-bombarded sample (or target). By convention, theenergy of the incident ion is denoted by E 0 or by E without a subscript.