ESE 521 S19 Kagan Problem Set 4.pdf - University of Pennsylvania ESE 521 Semiconductor Device Physics and Technology Due Prof C R Kagan Homework#4 1 A

# ESE 521 S19 Kagan Problem Set 4.pdf - University of...

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University of Pennsylvania ESE 521 Semiconductor Device Physics and Technology Due: March 27, 2019 Prof. C. R. Kagan Homework #4 1. A silicon step junction diode with a cross-sectional area A=10-4cm2has a doping of NA=1017/cm3and ND=1015/cm3. Let µn=801 cm2/Vs and τn=0.1 µs on the p-side; and let µp=477 cm2/Vs and τp=1 µs on the n-side. (a) Calculate the current through the diode at room temperature if (i) VA= -50 V (ii) VA= -0.1 V, and (iii) VA= 0.2 V (b) Assuming that the mobilities and lifetimes do not vary significantly with temperatures, repeat part (a) for T=500 K. (c) Summarize in your own words what has been exhibited by this problem. 2. The measured depletion capacitance of a p+-n silicon junction is shown. The devices area is 10-5cm2and the p+-layer thickness is 0.07 µm. Find the thickness of the n-type layer. 3. A p+-n silicon step junction is doped NA=1018/cm3and ND=1016/cm3where Ecr=4x105V/cm with ni=1010/cm3(kT =0.026 eV). Calculate: (a) VBR; (b) the depletion width at VBR. (c) If ND=1017/cm3repeat part (a) 4. A silicon step junction with an area of 10