Plasma Immersion Ion Implantation (PIII) is an established process technique in the area semiconductor device fabrication and surface modification. In this book, an attempt has been made to develop a generalized model of plasma load in a multispecies collisional PIII system that analyses the true electrical behaviour of the plasma load of PIII system during implantation of ions by evaluating various impedance parameters. To illustrate the validity of the model, mixed plasma of two species of He and Ar ions of equal ion density has been considered and it has been summarized that ion mass as well as the ion-neutral interactions play a key role in deciding the values and behaviour of these impedance parameters. This book is useful both as a graduate text as well as a research monograph for upcoming scientists, especially those who wish to explore the plasma load model at an analytical level.