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Unformatted text preview: UNIVERSITY OF CALIFORNIA SANTA BARBARA
DEPARTMENT OF CHEMICAL ENGINEERING CHE 142 and ChE 242: Microelectronics Processing £0 W
Spring 2003
Midterm Quiz (closed Book and closed notes, 50 minutes)
May 16, 2003 l) (8 points, 5 minutes) What is the crystal structure of Si and GaAs? Give the appropriate Bravais
lattice and the basis. What is the common name for these structures? How many Si atoms are there
in the conventional unit cell of Si? Si hasmmammd Wasc. GQHS “004M chuuelt Strum. Tho—aum‘ﬁvm
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A's mm air (W. W, Veda. ThPF‘L m 9 “Ms Gammrwflw 5‘ ”MW 2) (12 points, 6 minutes) Draw an band diagram for and indicate the approximate location of the Fermi
level at room temperature for a (a) intrinsic semiconductor (b) ntype semiconductor, and (c) ptype semiconductor. On diagrams for (b) and (0) show and label the donor and acceptor levels,
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(a) u/ri‘rLuch. lelmd. (to ”—131393' ( P 3'? 3) (6 points, 1 minute) What is the band gap energy in $0; Si and GaAs‘? (Eg)s?oz_ 5.; 2ev 4) (10 points, 6 minutes) Sketch (neatly) a MOSFET and show the source, drain, and the gate. Show
also the gate dielectric and the channel. /
P—‘l‘jpe SuitISM channel 5) (4 points, 1 minute) What are the leading gate insulator candidates to replace Si02 in the next
generation of MOSFETS? Hi0: , TIOL } %FOL)TQZOS (See page 9% oﬁ Com/phat) 6) (14 points, 7 minutes) Deﬁne and give the physical signiﬁcance (interpretation and meaning) of the
following dimensionless numbers: Re, Kn, Pc, PeT, (I), Gr. For each, say how they are useful.
Please be clear and communicate your responses clearly. “Re. ._ ued dawns“ {atom chamdmshhs , «2.45.3 lammur m» tutmm four
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Nowr , W3???WﬁﬁmﬁmﬁiiﬁﬁlﬁaﬁﬁﬁﬁEflfy‘tfoiéérafﬂe518:3iii}?!a};fi‘i'ntﬂaémmmwm‘ﬁia'E'HmztrW:Wa.m :‘cl.=FE'I'I‘K‘EEr‘N‘aﬂ‘:Wlewmwemrwirmwmﬁlmxwmmrvurvmwn...v............ .. ...... 7) (10 points, 6 minutes) Sketch how you expect the typical deposition rate to vary with temperature
in a CVD reactor for several different ﬂow rates. In your sketch, plot 10g of the rate versus MT.
Show the deposition reaction and mass transport limited regimes on this plot. What does the slope
of the curve in the reaction and mass transport limited regions tell you. rendw“ LIAtalk A “Slope:  E: I 461133014 mat/olvoﬂudho
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CON—r3” a—p slcpca.  ‘72.. 8) (5 points, 2 minutes) What is the functional form of the diffusion coefﬁcient of a species in solids? 9) (5 points, 2 minutes) What is the functional form of the diffusion coefﬁcient of a species in gas?
Speciﬁcally what is the form of the P and T dependence? 3) N Talia .n— ’P 10) (6 points, 4 minutes) What is mean free path? Give an equation which may be used to estimate
mean free path. What is the approximate mean free path of an Ar atom at I mTorr? meow Minna, bedroom colstm 51. am Wow Malcm wﬁHQ 3% {ohm gmbL—c __._l_____ (Am‘pw low M '4me
ENE? '"'”alli‘ﬁa’i‘rﬁmmm“???é‘iifméi’s!ﬁlﬁm‘lftfamedWﬁmﬁﬁmmhamlet:twmmmmmmmermmmmemm mymmrmanimatemaximmamaMW. ....... WWW ....... . WMWWWW 11) (10 points, 5 minutes) Sketch the MaxwellBoltzmann velocity and speed distributions for He and
Ar at same temperature. $017!) 12) (10 points, 5 minutes) Explain when one obtains each of the surface coverages Show below in a
deposition process. Suagace, dxbflumem (“OWL ‘77 rate 01.7 pFQWSdY'
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