{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Old_Exam_2solutions

# Old_Exam_2solutions - Georgia Institute of Technology...

This preview shows pages 1–6. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Georgia Institute of Technology School of Electrical and Computer Engineering EB 30400: Microelectronics Midterm Exam II NOTE: Please show all your work to obtain partial credit. The exam is closed book and notes. You may use one handwritten sheet of formulas. NAME Said! isrLS Grade: Problem ,1 (25 points) '-The concentration of extra carriers (Apn) at the two ends of an n—type Si sample of length L are kept constant at Apn (x=0) 0 and 'Apn (x=L)— — 10” (see ﬁgure below). There is no light illumination 1n the region 0 <x< L. The donor concentration in the sample 15 N13310“5 cm'3 Assuming steady-state condition prevails at T— 300 K: *' ‘ - "Simt-ype 7 he“ Nﬁiﬁ iﬁ'é (m3 _ (Holightl§<x<L) P9: ”9/99 g i236 {5m “to ,Q {@44 o (5) a. Do low—level in]K ection conditlons prevail inside the sample? Explain lift (6:63?“ << Erik ‘37 Léﬂ (8) _ I). Write the governing differential equation for the concentration of extra minority carriers (Apn (x) for 0 < x < L). Also write down a general solution for Apn (x) for 0 <x<L using two unknown parameters A and B. m3 A 73?: A i)“ ‘3wa (ijﬁgﬂ .,... - £11.?“ 2-: e (7) 0. Using the boundary conditions, find a set of equations for A and B You do not have to solve forAandB. Ea bir‘imma‘; Dian (Katie: Se “‘1? A +35 ~ <3 . , - 1.5: . ii; (5) (1. Establish an expression (based on A and B) for the hole current density 1,, ﬂowing in the sample at X = 0. i (J, l .53: ‘KD' ”K; ‘62.”... ‘ﬂ % ”Q! 1 ‘6? A Ty,» :51 3 {.357 2% is; h M Problem 2 (20 points) (10) a. The concentrations of donors and acceptors (in the n and p regions, respectively) 111 a step pn junction are ND=NA=1016 cm'3 .Draw the scaled energy band diagram of the pn iunction and ﬁnd the built- -1n voltage at T= 300 K. The intrinsic carrier concentration for Si at T= 300 K IS ni— m 1010 cm3 _ . f E; ‘ i" Side} 333:, 339,3: gm ﬁﬁwﬁ g) £31333,“ #7? nﬁf‘iﬁii 1’) is}: 51‘3“ w . ‘ ti; 3 w _ E ﬁldﬂ. x ESDSNAﬁriiD CM £327 hut?“ gig" 3K»; iﬂ. (536\$st 1338?? vi; m (10) b. A pn junction diode has the doping proﬁle ND - NA- — No [1-exp(-U. x)] as shown in the ﬁgure below. Assume that the depletion approximation in valid, and the depletion region is —x;, < x < Xn. Sketch the charge density in the diode, and ﬁnd and sketch the electric ﬁeld in the depletion region. §§ sﬁ i 35333 333333 “‘§?<‘?< <33 Problem 3 (20 points) Find and plot the transfer characteristics (v0 versus vi) for the following circuit Assume both diodes are ideal. "3‘23: 5. Q; 3 of, 3641::ng 3mm WWW-r ""3 ‘3 “24- 23;: :3 {w as“: 5" @333: KQN 3.333333 3 ‘ 3\'_ i” ON 35‘ N 1m» 1; V3233 1M) f \ W -‘, V g CMl . Bi 0.4;; D21 Q{\J g) \{S 36mg; v a" C? V \ 3 m lv 3 A .2: ~m £3. \x.» QGQKDEPES “25:3”: (“3‘3"”233“ "(Lffimgvkt 3:3 w 3 5 «2: a: :22 “39:“ x 3:331» 833‘”; 2:23 ”333323333 23*“, 331.2323) ,1 Xg{>\1 Eigvgtﬁé'é 3.3; :3 . , 5'” a: w-.. 3 w»: Wm.» E); 53?? :5;; Vgtizgi? 22:42:? Wiéé‘i’j 2:: \$3333“ "““ \$333”:3x‘;£~ “3: ,:::3 ' '3: ‘M W“ :J“”"’“ mold .339} ‘7‘ ,W.~3WW”°%V ”M“ “' 3‘? 33°}: “ ‘33 5333:3333 533‘”? “5:2 We: (5:? {3+} ‘30 3:331 E21...“ #9 33‘3“" “3 \s 7. TMV “3‘2;ng :3??? A“ 3m: ””2533“ :5; 6.37:: 533,333 >9 \f/ 3‘ Lmuwwim WWW“ WW»? V3 1631) . my? t ‘3} 3} \$7 333 5%? Q “we”? V 5 ‘5‘ 1%,}1’3». ED '21 _ I“ V3.“ “I” W 30; 3 is‘ “my, § ’5: 3 :3 D “To a _- )ia‘béffl :3 {a y ‘5) \ i w..._ C“ 5‘“ 3:.31 of; (l); «51.3.3 may so! 5” ’33; 533;; 33“” w £34233“ :9 W ""1W’WM 3‘ .3 “23" “IE V v: “*9" 333333331}; “fl“! 313V <2L\ +2; {ﬂew {3% a ‘E Problem 4 (20 points) The collector and base of an npn transistor are connected together, and a voltage VA is applied between collector and base as shown in the ﬁgure below. Using Ebers-Moll model: (10) a. Derive the I'VA relationship. T11; T? .. 059.. 3p :4 WEE; V3630 x V33; ﬁvﬁx a}? 6% “Efﬁe; : 1:3?s {ﬁx wk) —G{E1€&QK€: (10) b. Develop expressions for Ans (0) / nm and A113 (W) / 1130 in terms of VA and the Ebers— M011 parameters. mew SEE/law WM?“ } .., mggg; m, m w M gm?) WE ﬂv‘géﬁw p ":1, £33 @3337 a w W Problem 5 (20 points) In the circuit shown below, ﬁnd the power dissipation in the zener diode in the following two cases: \ - 150 Q (10) a. RL=75 Q Aéb‘JM ~§~ﬁ=a New ﬁg {3&6 {a gag “m 1M mg; m, .n «Mammy; at. an WW“ 3.41:5“?an eagegf A} g .1; %§"., MUM: it; a “33’ “WEQWEQBEA :fgi‘éA PG fﬁjﬁx\g ”‘7' i \g‘“ M: ‘ (10) 1). RL 2 co 55“}5‘} M‘ éém 2 «HQ/mew” aﬁuhm 3-25! jive Eﬂl-é’iﬁfﬁ' QM: ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 6

Old_Exam_2solutions - Georgia Institute of Technology...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online