Mid-Term Exam with Solution
Elec221
Final Exam
December 14, 2002
7. The slight slope of the collector current with increased collector voltage in the common-emitter characteristics of a BJT is called the ________early_____________ effect which is a result of ______________base width modulation_____________________.
Short Questions (1 point for each blank)
8. The total capacitance of an ideal MOS structure includes the capacitance of ____SiO2_______ and the capacitance of _____depletion_region____________. 1. The Hall effect measurements yield the following information about a piece of semiconductor : ____type of the material___________ , ______doping concentration_____________ , _________mobility________________________. 9. For a realistic MOS structure, the threshold voltage (VT) should include two terms in addition to those in the ideal model, representing _____work function difference________and ________________interface charge________________. 2. Reverse biasing of a p-n junction is to connect a positive voltage to the ______n_______-side of the junction. Under reverse bias, the energy band separation (electrastatic potential barrier) across the junction is _____larger_____ than at equilibrium. The electric field is _____increased_____ and the transition region width is______increased______ with increasing magnitude of reserve bias. 3. In a forward-biased n+p-junction, the forward current is due to injection of ___electrons_____ from _______n______ to ________p______, resulting in a large diffusion / drift (circle one) current which flows from ____p______ to ______n______. 4. The reserve breakdown of a p+n-junction increases as the concentration of donors / acceptors (circle one) ________decreases_________. 5. The reserve breakdown of a heavily doped junction (p+n+) is due to the ______zener_______effect, which is a result of______tunneling__________________. 6. The zero bias junction capacitance of a n+p junction is high if the concentration of donors / acceptors (circle
Final Exam
December 14, 2002
7. The slight slope of the collector current with increased collector voltage in the common-emitter characteristics of a BJT is called the ________early_____________ effect which is a result of ______________base width modulation_____________________.
Short Questions (1 point for each blank)
8. The total capacitance of an ideal MOS structure includes the capacitance of ____SiO2_______ and the capacitance of _____depletion_region____________. 1. The Hall effect measurements yield the following information about a piece of semiconductor : ____type of the material___________ , ______doping concentration_____________ , _________mobility________________________. 9. For a realistic MOS structure, the threshold voltage (VT) should include two terms in addition to those in the ideal model, representing _____work function difference________and ________________interface charge________________. 2. Reverse biasing of a p-n junction is to connect a positive voltage to the ______n_______-side of the junction. Under reverse bias, the energy band separation (electrastatic potential barrier) across the junction is _____larger_____ than at equilibrium. The electric field is _____increased_____ and the transition region width is______increased______ with increasing magnitude of reserve bias. 3. In a forward-biased n+p-junction, the forward current is due to injection of ___electrons_____ from _______n______ to ________p______, resulting in a large diffusion / drift (circle one) current which flows from ____p______ to ______n______. 4. The reserve breakdown of a p+n-junction increases as the concentration of donors / acceptors (circle one) ________decreases_________. 5. The reserve breakdown of a heavily doped junction (p+n+) is due to the ______zener_______effect, which is a result of______tunneling__________________. 6. The zero bias junction capacitance of a n+p junction is high if the concentration of donors / acceptors (circle