SOLUTION: IME 2009 Microelectronics 2 | My Assignment Tutor

YSGOL CYFRIFIADUREG A PHEIRIANNEG ELECTRONIGSCHOOL OF COMPUTER SCIENCE AND ELECTRONIC ENGINEERINGArholiadau Diwedd Semester 2End of Semester 2 Examinations2018/2019IME 2009Microelectronics 2Amser a ganiateir: 1½ awrTime allowed: 1½ hoursCyfarwyddiadau / Instructions:Answer all questionsTotal marks 100Trowch y dudalen drosodd pan ddywedir wrthych / Please turn over when instructed2IME 2009: Microelectronics 2Physical constants:Electronic charge, e = 1.6×10-19 CPermittivity of free space, ε0 = 8.85×10-12 F m-1Boltzmann’s constant, k = 1.38×10-23 J K-1 = 8.62×10-5 eV K-11. Calculate the electron and hole concentration under steady state illumination in an n-typesilicon with charge carrier generation rate due to light GL = 1016 cm-3s-1, donor concentrationNd =1015 cm-3, and charge carrier lifetime e = h = 10 µs. [10]2. If minority carriers are injected into a p-type semiconductor sample, calculate their diffusionlength, assuming that the carrier mobility is 0.4 m2V-1s-1 and the lifetime of minority carriers is0.6 ns at 300 K. [10]3. Consider an abrupt pn junction model where Na is the acceptor doping density and dp, the widthof the depletion region on the p-type side. Using the Poisson’s equation (eq.1), show that themaximum electric field (Emax) in a one-sided pn+ diode at the junction is given by equation(eq.2). ?2 ?(?)= –?(?)=? ??? ??(eq.1)??2? ?? ???? = –? ?? ??? ??(eq.2)[10]4. Briefly explain what is meant by a “narrow diode” and “one-sided diode”, and provide anexample for their application in electronic devices. In addition, explain how electricalbreakdown occurs in these devices. [20]5. Briefly explain the operation of bipolar junction transistors when biased in the active mode. Inyour answer, use a suitable diagram and highlight why the performance of this type oftransistor depends mainly on the diffusion of minority charge carriers. [16]36. Consider a Metal-Oxide-Semiconductor (MOS) capacitor formed on a silicon substrate. Thehigh-frequency capacitance-voltage (C-V) characteristics for such capacitor is shown in Figure1.Figure 1(i.) From the (C-V) characteristics shown in Figure 1, is the semiconductor p-type or n type? Explain why.On Figure 1, identify the accumulation, depletion and inversion regions.[4][6] (ii.) 7. With the aid of diagrams, explain the operation principles of n-channel MOSFET. [10]8. Using energy band diagrams, explain the differences between a Schottky contact and Ohmiccontact when a contact is formed with an n-type semiconductor. [14]