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Unformatted text preview: ECE 3080A: Homework #5 Due Date: Nov. 2, 2007 Page 1 of 2 G EORGIA I NSTITUTE OF T ECHNOLOGY S CHOOL OF E LECTRICAL AND C OMPUTER E NGINEERING ECE 3080A: Semiconductor Devices for Computer Engineering and Telecommunication Systems Fall Semester 2007, Homework #5 Homework Due Date: Friday, November 2, 2007 1. BJT: Transistor Parameters (20 points) Compute α , α T , γ , and β for an npn BJT that has the following parameters: N E = 10 19 cm-3 , N B = 2 10 17 cm-3 , N C = 10 17 cm-3 , V BE = 0.8 V, V CB = 2.0 V The metallurgical widths of the emitter and base regions are W E = 0.2 μ m and W B = 0.2 μ m (note that the transistor has a short emitter!). Use D E = 3.8 cm 2 /s and D B = 15 cm 2 /s for the diffusion coefficients. 2. BJT: Minority Carrier Distribution (15 points) A silicon npn BJT is uniformly doped and biased in the forward active region . The neutral base width is W B = 0.8 μm. The transistor doping concentrations are N E = 5 10 17 cm-3 , N B = 10 16 cm-3 , N C = 10 15 cm...
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- Bipolar junction transistor, P-n junction, minority carrier concentrations, base width, ECE 3080A