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As is evident from Fig. (6.24) W, the base width, is limited by the resolution of the photolithographic technique which is 10um in 1960s. Also punch through has to be avoided. (Punch through occurs when C-B depletion region overlaps E-B depletion region; at this point excessive current flows and transistor action is lost ). Therefore in lateral transistors W is 5 to 10um. This large W causes a drastic deterioration of short circuit current (β fo ) and transit frequency (ω T )

From our device physics we know that Transit Time = τ transit = W 2 /(2D B ) and β fo = (τ recombination / τ transit )

Also since P doping of emitter (10 17 /cc) and collector (10 17 /cc) is heavier than N doping(10 16 /cc) of the epilayer which is base here, the depletion width extends into base region predominantly. This causes δW/δV CB to be significant which leads to significant Early Effect hence h ob and h oe (or g c and g o ) are large (the slope of I-V characteristics is large) But here BV EBO = BV CBO high is quite high.

Because of poor performance parameters of lateral transistors, the latter are fully avoided for high frequency applications. But in low frequency applications (typically below 1 MHz ) a mix of n-p-n and lateral p-n-p can give very favorable performance characteristics. Therefore such a mix is used in uA 741.

Section 6.10 Breakdown voltages of n-p-n transistor in MC1530

Referring to the doping profile of n-p-n transistor in Fig. (6.17) it is seen that

background doping of the epi-layer is N BC = 1.2 × 10 16 (cm -3 )

and N’ B = 1.8 × 10 17 (cm -3 ), emitter doping is N E =1.0 X 10 20 (cm -3 ) and W = 0.7 um.

Therefore

BV CBO (determined by N BC ) = 55V.

BV EBO (determined by N B ’) = 7V.

BV CEO = BV CBO / (β o ) 1/MillerIndex = 23V

[Substrate pnp transistor :- Here p substrate is used as collector and n epilayer is used as base and p layer, for the base diffusion in npn transistor, is used as emitter. Since here W depends upon diffusion depths therefore much better performance parameter as compared to lateral pnp can be achieved. But substrate pnp can be used only in CC configuration.]

Doping profile of pnp transistor is given in Fig. (6.25)

As is evident from Fig. (6.25)

N B ’ = N BC

Therefore BV CBO = BV EBO = 55v.

Therefore if lateral pnp transistor is used in the input circuit of Op-Amp (as it is done in uA741 ) a much larger V id (differential mode signal ) can be handled by the Op-Amp.

Section 6.11 Design Considerations in the circuit layout of MC1530/31.

We have already seen the fabrication steps involved in the manufacture of MC 1530 or MC 1531. Now we will examine the design considerations involved in the circuit layout of MC -1530 on the silicon chip. MC-1530 and MC-1531 are identical circuits except for the input differential stage. MC-1530 is a direct input to a differential stage with R id = 10K whereas MC-1531 is a darlington pair input to the differential stage with R id = 1M.

We have already seen that N epi layer of the isolated island forms the collector of the transistor or the anode of the diode. ( We have shown in Sec. 6.5 that transistor is used in diode configuration by shorting collector to base). Therefore N epi layer of any isolated island will always be at some positive potential as dictated by d.c. quiescent condition of the circuit. These positive potentials set the proper operating condition of the circuit as well as they help isolate the components from the substrate and from one another.

Questions & Answers

Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
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Brian Reply
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Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
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hi
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Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
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