P-N Junctions and Their Breakdown Mechanisms

P-N junction is an important control element for the performance of semiconductor devices. Devices such as amplifiers, rectifiers, linear and digital ICs etc. employ one or more P-N junctions for their working. Therefore, for a good understanding of all these, the P-N junction diode: their applications and working at equilibrium conditions are presented. In this chapter, relations have been established between contact potential and doping concentrations, for Fermi level at equilibrium, for the width of depletion region and penetration depth. Biased junctions: their working when not connected to a battery, forward-biased and reverse biased p-n junctions and their voltage-current characteristics are described. Poisson’s equation, junction breakdown mechanisms, Zener and avalanche breakdown, and junction capacitance are discussed. Rectifying diodes, half-wave rectifiers, Zener diode for electric meter protection and as peak clipper are given. The breakdown diode; specifications of p-n junction diode, their physical structures and terminal identifications are also elaborated. Minute insight into the various topics are given through solved numerical and theoretical examples. Review questions, numerical problems and objective type questions are also given with their answers.