This clear, student-oriented text is for upper-level or graduate courses covering basic semiconductor physics, physical descriptions of PN-junction diodes, bipolar junction transistors, and MOS Field-effect transistors. The organization is from specific to more general topics with a foundations chapter that reviews critical concepts such as Poisson's Equation, dielectric relaxation, and displacement current. The text progresses toward detailed and often unique coverage: including SPICE modeling of the junction diode, the BJT and MOSFET, ohmic-contact application of the high-low junction, and MOS-capacitance crossover.