This class is an introduction to the physical principles of semiconductor devices and their fabrication technology. It is intended to incorporate the basics of semiconductor materials and conduction processes in solids, which arise repeatedly in the class when new devices are explained. One of the keys to success in understanding the semiconductor physics is to work problems that exercise the concepts. Therefore, three or four problems at the end of each chapter are assigned to the homework every week. In addition, we apply the knowledge learned in class directly to electronic devices such as pn junction and light-emitting diodes, through AMPS-1D Simulation. The class includes both silicon and compound semiconductors, to reflect the continuing growth in importance for compounds in optoelectronic and high-speed device applications.