Electronics has revolutionized the world in many ways than any one has thought before. Working of Electronic Devices & Circuits is owed to the properties of semiconductor. In this subject, physics of semiconductors has been elaborately studied along with concept of doping using which p and n-type materials are formed. Later on, p and n materials are combined to form diodes and Transistors namely BJT, JFET and MOSFET etc. MOSFET and ICs that very much belong to the current generation of electronics based on which further developments are made.