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These PowerPoint color diagrams can only be used by instructors if the 3rd Edition has been adopted for his/her course. Permission is given to individuals who have purchased a copy of the third edition with CD-ROM Electronic Materials and Devices to use these slides in seminar, symposium and conference presentations provided that the book title, author and © McGraw-Hill are displayed under each diagram.

Metal interconnects are used in microelectronics to wire the devices within the chip, the intergraded circuit. Multilevel interconnects are used for implementing the necessary interconnections.

|SOURCE: Dr. Don Scansen, Semiconductor Insights, Kanata, Ontario, Canada

Fig 2.26

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

Drift of electrons in a conductor in the presence of an applied electric field. Electrons drift with an average velocity vdx in the x-direction.(Ex is the electric field.)

Fig 2.2

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

V ib ra tin g C u + io n s

ux

Ex

V

(a) (b)

(a) A conduction electron in the electron gas moves about randomly in a metal (with a mean speed u) being frequently and randomly scattered by by thermal vibrations of the atoms. In the absence of an applied field there is no net drift in any direction. (b) In the presence of an applied field, Ex, there is a net drift along the x-direction. This net drift along the force of the field is superimposed on the random motion of the electron. After many scattering events the electron has been displaced by a net distance, x, from its initial position toward the positive terminal

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

tim et2 t

E le c tro n 2

v x 2 ­ u x2

t im e

v x 1 ­ u x1

t1 t

L a s t c o l l is io n

F r ee t im e

E lectron 1

P re se n t t im eV e lo c ity g a in e d a lo n g x

tim et3 t

E lectron 3

v x 3 ­ u x 3

Velocity gained in the x-direction at time t from the electric field(Ex) for three electrons. There will be N electrons to consider inthe metal.

Fig 2.4

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

t1

s = x

C ollision

S tart

F in ish

E lec tr ic f ie ld

E

t2

x

C o llision0

2

1

p

s1

ux1

uy1

3

4

t3

D is ta n c e d r if te d in to ta l t im e t

The motion of a single electron in the presence of an electric field E. During a timeinterval ti, the electron traverses a distance si along x. After p collisions, it has drifted

a distance s = x.

Fig 2.5

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

a

u

E le c tro n

S = a 2

Scattering of an electron from the thermal vibrations of the atoms. Theelectron travels a mean distance = u between collisions. Since thescattering cross sectional area is S, in the volume S there must be atleast one scatterer, Ns(Su) = 1.

Fig 2.6

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

I

S tra in e d re g io n b y im p u ri ty e x e rts asc a t te r in g fo rc e F = ­ d (P E ) /d x

Two different types of scattering processes involving scattering fromimpurities alone and thermal vibrations alone.

W.F. Beadle, et. al.,”Quick reference manual for semiconductor engineers,” Wiley, NY, 1985.

Silicon electron mobility

Mob

ility

(cm

2 /V

-s)

Diff

usiv

ity (

cm2 /

s)

Fig 2.7

From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)

The resistivity of various metals as a function of temperature above 0°C. Tin melts at 505 K whereas nickel and iron go through a magneticto non-magnetic (Curie) transformations at about 627 K and 1043 Krespectively. The theoretical behavior ( ~ T) is shown for reference.[Data selectively extracted from various sources including sections inMetals Handbook, 10th Edition, Volumes 2 and 3 (ASM, MetalsPark, Ohio, 1991)]

T

T u ngsten

Silver

C o p p er

Iro n

N ickel

P latinum

N iC r H eating W ire

T in

M on el-4 00

Incon el-8 25

10

100

1000

2000

100 1000 10000

T em peratu re (K )

Res

istiv

ity(n

m)