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Unformatted text preview: from the doping if the bar is to have a resistance of 1.5 K ? ? Assume nominal room-temperature values for all silicon parameters. Ans: Because the material is doped with Phosphorus, it is N-type For N-type conductivity ? ? n*u n *q n , u n =0.14m 2 /vs Then R= ? *l/A=l/(A* ? )=l/(A*n*u n *q n ) n=l/(R*A*u n *q n )=0.1*10-2 /(1.5*10 3 *8*10-8 *0.14*1.6*10-19 ) =3.72*10 20 Carriers/m 3 4) A silicon PN junction is formed from N material doped with 2.5*10 21 donors/m 3 and P material doped to have the same impurity density. Find the thermal voltage and barrier voltage at 20 ? c. Ans: V T =KT/q=1.38*10-23 *(273+20)/(1.6*10-19 )=25.27mv V ? =V T ln(N A* N D /n i 2 )=25.27*ln((2.5*10 21 ) 2 /(1.5*10 16 ) 2 )=0.607v 5) A diode has a saturation current of 45PA at a temperature of 273k, what is the approximate value of I s at T=373k? Ans: I s =2 10 *45PA=46080*10-12 A=4.6*10-8 A...
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This note was uploaded on 11/14/2009 for the course DAL ECED 3201 taught by Professor Sankary during the Spring '09 term at Dalhousie.
- Spring '09