Roll No.

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TotalNo.ofQuestions:09] Paper

ID [D EO 12

[Total No. of Pages: 02

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(Pkasl' fill this Paper ID in 0:\'1 R Shl'(.t)

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B.Tech. (Semester - 6th ~ICROELECTRONICS

& 7th)

(DE 1.2)

Time: 03 Hours'

Maximum Marks: 60

Instruction to Candidates: /'--.

1)

Section - A is COll1pulsory.

2)

Attempt any Four questions from Section - B.

3)

Attempt any Two questions from Section

- C.

Section -A Ql)

(10 x2 =20) a) What are the advantages of using Si-Si02 system? b) Compare the two techniques: Liquid Phase Epitaxy and Vapour Phase Epitaxy. '

c) What is meant by projected range and straggle in implantation? d) How are diodes realized in IC'technology? Draw it. e) How are the patterns generated to make a mask? f)

Explain Flip-chip technique.

g) What is the significance of VT in MOS design? How is it adjusted? h) What is the significance of MEMS technology? i)

Differentiate between thin film and thick film circuits.

j)

Explain the principle behind the metallization process. How is it carried out? - Section -

B (4x5=20)

Q2) How is good quality thin oxide layer grown? What are the techniques used to remove the charges in oxide and traps at Si02-Si interface? ' J-557

P.T.O.

Q3)

Use photolithography technique to explain lift-off process of metallization. Draw suitable figures to explain the process.

Q4)

Find the value of resistor 100 /-lm long and 10 ~L1n wide, such as the b2.t:shaped resistor. The sheet resistance is 1 kQ[].

Q5)

A Si crystal is to be grown by the Czochralski method, and it is desired that

the ingot contain 1017phosphorus atoms/cm3 :

.

(a) \Vhat concentration of phosphorus atoms should the melt contain to give this impurity concentration in the crystal during the initial growth? For Pin Si, kd= 0.35. (b) If the initial load of Si in the crucible is 10 kg, how many grams of phosphorus should be added? The atomic weight of phosphorus is 31. Q6) Explain the process of rapid thetmal annealing (RTA). Discuss its signifiCance in IC processing. Section - C

(2 x 10 =20) Q7) (a) Discuss various isolation techniques used in rcs. (b) Discuss the technique of reactive ion etching. Give its applications. . . Q8) (a)

What is the stored charge and the number of electrons on a MOS capacitor with an area of 8 /l m2 for a dielectric of (i) 12-nm thick Si02 and (ii) 5-nm thick Ta2Os? The applied voltage is 5 V for both cases. (b) Use positive resist-photolithography to fabricate a bipolar junction transistor. .

Q9) (a)

For an integrated inductor with an inductance of 10 nH, what i~the required radius if the number of turns is 20? (b) Write notes on: Bonding and Packaging (lCs).

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