Smd Tutorial

7/31/2019 Smd Tutorial

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GLA University Mathura

Semiconductor material Device

Tutorial#1

1.Explain electrical absorption with energy band diagram.2.Derive the expression for intensity of light when it will

transmitted through sample thickness L.

3.What do you mean by photo luminance explain.4.Explain the phenomenon of electroluminescence. derive the

expression for carrier life time.

5.What is photoconductivity explain.6.Derive the formula for photoconductivity in terms of carrier

life time.

7.What do you mean by direct and indirect semiconductor?8.Explain direct indirect recombination.9.What is difference between drift and diffusion?10.What is contact potential explain.


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Tutorial#2

1. Derive the expression for contact potential.

2. What is Fermi energy level explains.

3. What is direct and indirect recombination explains.

4. Discuss the continuity equation.

5. Derive the Einstein equation.

6. What do you mean by diffusion length derive.

8. Explain Haynes Shockley experiment.

9. A semiconductor in thermal equilibrium has hole concentration

of po=1016cm-3 and intrinsic concentration of ni =1010cm-3. the

minority carrier life time is 210-7

sec

(I)Determine thermal equilibrium recombination rate of electron.

(II)Determine change in recombination rate of electron if an

excess concentration of electron n=1012/cm3

exciting .

10. Define the diffusion length and derive the hole concentration

as a function of x.


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Tutorial#3

1.Define the contact potential and derive the formula for contact

potential in terms of NA and ND

2 The hole concentration in semiconductor specimen is shown inFig2: Find the value of hole current density if diffusion coefficientis Dp.

3. Calculate the built in potential barrier in p-n junction .Consider a

silicon p-n junction at T =300 K with doping density NA=1018 ,

ND=1015/cm3, assume ni = 1.5x1010/cm3.

4. What is the continuity equation discuss in brief.

5. what is the Poissons equation? Find the width of transition region

W in terms of contact potential and doping concentration NA and

ND. Consider p-n junction is unbiased.

6. Assume that a photo conductor in shape of bar of a length L and

area A has constant voltage V applied. And it is illuminated such that

gop EHP /cm3-s are generated uniformly throughout. If n and p

are mobility of electron and hole and n and p are lifetime for

electron and hole . Show that I =qgopLA(n + p

)/ t . where t is

transit time of electron drifting down the length of bar.


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Tutorial#4

1.Explain metal semiconductor junction with energy banddiagram.

2.What is schottky barrier? Explain3.What is basics difference between rectifying contact and ohmice

contact?

4.Explain the operation of photodiode draw the characteristics.5.Explain the operation of solar cell and draw the characteristics.6.Explain the operation of photo detector and draw the

characteristics.

7.Explain the operation of LED and draw the characteristics.8.Explain the operation of LASER and draw the characteristics9.What do you mean by population inversion at junction explain.


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Tutorial#5

10. Explain the operation of tunnel diode with energy banddiagram and draw the characteristics.

11. Why tunnel diode is negative resistance diode explains.12. Tunnel diode can be used as oscillator how?13. Explain the operation of IMPATT diode and draw the

characteristics.

14. What is Gunn Effect explains.15. Conductivity of n-type GaAs Gunn diode?

Given that Electron density is n=1018

cm-3

, Electron density at

lower valley is nl=1010

cm-3

, Electron density at upper valley is

nu=108

cm-3

, temperature T =300K.

16. Characteristics of n- type GaAs Gunn diodeThreshold field Eth= 2800V/cm, Applied field E= 3200V/cm,

Device length L=10m, doping concentration no=21014

cm-3

operating frequency f = 10GHz then find (a) electron drift

velocity (b) current density (c) negative electron mobility.

17. For transit time domain mode, the domain velocity is equal tothe drift velocity and is about 107cm/s. determine drift length of

the diode at frequency of 8 GHz.


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Tutorial#6

1.Find the concentration of electrons and holes as a function of x inbase region of BJT.

2. (a)Find the expression for current I for the transistor connectionshown if =1.

(b) How does the current I divide between the base lead and

collector lead?

3. Describe charge control analysis of BJT transistor.

4. Describe the drift phenomenon in base region of BJT.

5. Describe base narrowing in BJT.

6. What is avalanche break down? Explain.

7. Describe the operating principle n-type enhancement MOSFET.


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Tutorial#7

1. Derive the relation between IDS & VDS for n-type enhancement

MOSFET in saturation region and ohmice region.

2. Describe the operating principle n-type depletion MOSFET.

3. Can you operate n-type depletion MOSFET as a n-type enhancement

type MOSFET?

4. In an enhancement mode n-type MOS the device parameter were

given as VGS = 3V, Vds =5V, Vth= 1V nCo =25A/V2,ID =0.25mA findout value of aspect ratio of transistor and also obtained length and

width of channel.

5. Describe the operating principle of n-type GaAs MESFET.

6. Describe the operating principle of high electron mobility transistor.


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