Semiconductors HW 5

The mode of operation for the D-MOSFET is Select one: a. the ohmic region only b. the enhancement mode only c. both the depletion and enhancement modes d. the depletion mode only

Explain the concept of Moore's Law and its implications for the semiconductor industry. Assess whether it is still relevant in the era of nanometer-scale transistors.

a) Figure B3 shows a cross section for a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) in diagrammatic form. (i) (ii) Sketch the energy band diagram for the MOSFET along the line X-Y shown in Figure B3 when bias voltages are applied such that the silicon surface is inverted. Label all important features of your sketch and state any assumptions made. Sketch a box plot showing the charges present in the structure when the silicon surface is inverted. Indicate the source of all the charges and state whether they are positive or negative. Source n+ Metal Silicon Substrate - p X dioxide Drain n*

A 4.7 zener diode is connected to the base resistor. The left side of the resistor sits at about 12V. The right side of the biasing resistor is connected to the Zener and npn transistor. The Zener bias is 5mA. The base current needed is 80uA. What is the appropriate resistor for this circuit? (In kohms) I

1N4001, 1N4002, 1N4003, 1N4004, 1N4005, 1N4006 and 1N4007  For any of the diodes, describe with the aid of diagrams/illustrations its applications in an AC to DC Bridge rectifier power supply circuit. For your circuit show and describe how you are going to smooth out the ripple voltage that will be present.

Describe how a silicon wafer is manufactured starting with pure solid silicon and explain why this is important to the function of solid state devices.

Describe and evaluate a range of discrete semiconductor devices in terms of simple semiconductor theory Critically evaluate the performance of a range of discrete semiconductor devices in terms of simple semiconductor theory, and suggesting appropriate applications for each.

A Full-wave bridge rectifier Circuit contains 4 Germanium diodes Cuse the Constant voltage drop model with VD = 0.30) driving ac a Load resistance of 10 kur. An Source with a Peak value of 4ou at bottz Vortage Source with a applied to the Circuit. a DIS 2 Determine the de value of the output wave form Determine the value of the Capacitor In uf needed to limit the output ripple vortage to 0.5 V if the Peak output voltage is equal to Upic -2VD

Explain the operation and Analyse the performance of a range of discrete semiconductor devices used in modern electronic systems in terms of simple semiconductor theory, and suggesting appropriate applications for each, such as: Triac. • MOSFET. Thyristors.

1. Fill in the gaps with appropriate words: (5x1=5) A. If the peak input voltage of a half wave rectifier is 28V then the diode used should have PIV rating of at least.... B. To prevent a DC return between source and load, it is necessary to use... . .between source and load. C. Common emitter transistor configuration has best D. In the breakdown region, a Zener diode behaves like a E. Introducing a resistor in the emitter of a common emitter amplifier stabilizes the de operating point against changes in.. ..gain. ....... Source. 2. Answer the following question in short: (5x2=10) A. Why 180 degree phase shift occur in CE configuration? B. Draw the input characteristics of CE configuration and explain the effect of VcE on it. C. A power supply A delivers 10 V de with a ripple of 0.5 V r.m.s. while the power supply B delivers 25 V de with a ripple of 1 mV r.m.s. Which is better power supply? D. The applied input A.C. power to a half-wave rectifier is 100 watts. The D.C. output power…

Q6) d) Show by means of a diagram how you will normally connect external batteries ini. PNP transistorii. NPN transistore) Describe how a semiconductor will behave at absolute zero temperature.

05: Choose the correct answer: 1. The current in FET flows between terminals. (Drain and gate Drain and source Gate and soarce None of these) 2. The threshold voltage is in enhancement type metal oxide semiconductor field effect transistor. (Positive Negative Zero Positive) 3. The drift current density effected by (An electric filed • Concentration gradient in holes • Concentration gradient in free electrons All of these) 4. The band gap between conduction and valance band in an insulator is (Low Very low High Moderate) 5. Operating point of a transistor must be independent of (Biasing Amplification Variations in parameters Filtration) 6. When a transistor operating at the central of the load line is declining, the current gain will change the Q-point (down up nowhere of the load line) 7. A bipolar junction transistor when used as a switch, operates in (cut-off and active region active and saturation region cut-off and saturation region all of these) 8. Inversion layer in an MOS…