Download Thermal - Microelectronic Devices and Circuits - Exam and more Exams Microelectronic Circuits in PDF only on Docsity! University of California at Berkeley College of Engineering Department of Electrical Engineering and Computer Sciences R.T. Howe, Fall 1997 EECS 105 Midterm I: October 8, 1997 · Closed book and notes; one 8.5" X 11 "formula sheet (both sides) · Do all work on exam pages · You have 80 minutes; use your time wisely! Problem #1 MOSFET LAYOUT [18 points] Untitled Document 1 Untitled Document
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b) [4 pts.] Find the numerical value of the small-signal resistance r at the operating point Vsup=4V. c) [6 pts.J We now use the resistive element as the load in an inverter. Using the load-line technique on the Id =Isup versus Vout graph, sketch the transfer curve Vout versus Vin on the graph below. You should have intersection points for input voltages Vin= 0, 1, 2, 2.5, 3, and 4 V. Given: MUnCox = 50 uA/V^2, Vtn = 1 V, (W/L) = 4/2 = 2, and LAMBDAn = 0 Untitled Document 5 d) [4 pts.] Find the numerical value of the slope Av of the transfer curve found in part (c) at Vin = 2.5 V. Given: the MOSFET is saturated for this value of Vin. Note: it is not necessary to solve part (c) to answer this part. Problem #3 Metal/p/n/Metal Capacitor [15 points] Given: q = 1.6 x 10^-19 C, EPSILONs = 1.04 x 10^-12 F/cm, 1 A = 10^-8 cm; 1 um = 10^-4 cm a) [4 pts.] From the plot of charge stored (on the p-side of the junction) versus the diode voltage below, the Untitled Document 6 charge for Vd = 0 V is -8 x 10^-8cm-2. What is the overall depletion width Xdo for this case? b) [4 pts.] Sketch the capacitance (units: F/cm2) versus diode voltage for this metal/p/n/metal structure on the graph below. Given: Xd = 4000 A for Vd = -2.4 V and Xd = 6000 A for Vd = -6.4 V If you couldn't solve part (a), you can assume without loss of credit that Xdo = 1500 A for Vd = 0 V (... not the correct answer to (a), of course). Your plot should be accurate at these voltages. c) [4 pts.] Sketch the charge density RO(x) through the structure for Vd = -10 V on the graph below. The relative magnitude of the densities and any sheet charges (shown as delta function "spikes") should be correct; there is no need to find numerical values. Untitled Document 7
