Linear Integrated Circuit Quizon “Active and Passive Components of IC – 2”.
1. The number of leads in schottky barrier diode are
A. Four
B. Three
C. Two
D. Six
Answer: C
Clarification: Schottky barrier diode has two contact leads namely,
1. Schottky Barrier contact
2. Ohmic contact.
2. In Schottky barrier diode, which contact has similar characteristics to that of an ordinary PN diode?
A. Ohmic contact
B. Schottky barrier contact
C. Both ohmic and Schottky barrier contact
D. None of the mentioned
Answer: B
Clarification: A metal semiconductor is formed when aluminium is deposited directly upon n-type silicon. Its characteristics is found to be same as in an ordinary PN junction diode (Although the physical mechanism is different).
3. Find the symbol for Schottky barrier diode from the given circuit diagram?
Answer: A
Clarification: The mentioned symbol is the symbol for metal semiconductor diode or Schottky diode.
4. How the ohmic contact is formed in metal semiconductor diode? (AL-Aluminium)
A. n+ diffusion in p-region near AL lead
B. p+ diffusion in p-region near AL lead
C. n+ diffusion in n-region near AL lead
D. p+ diffusion in n-region near AL lead
Answer: C
Clarification: Aluminium is p-type impurity in silicon. So, when it is used to make a contact with n-type silicon, its essential contact is ohmic and no PN-junction is formed. Therefore, the contact is done by making n+ diffusion in the region near the surface where aluminium is deposited.
5. The flow of current in Schottky barrier diode is due to
A. Majority and Minority carriers
B. Majority carriers
C. Minority carriers
D. None of the mentioned
Answer: B
Clarification: When the diode is forward biased, electron flow from semiconductor to metal (where electrons are abundant). Hence, the majority carrier ‘electrons’ carry current in Schottky diode.
6. Find the application areas, where Schottky diode can be used?
A. Radio frequency
B. Power rectifier
C. Clamping diode
D. All of the mentioned
Answer: D
Clarification: Schottky diode can be used for ideal clamping or as detector in high frequency microwave ICs. Therefore, it is used for all these applications.
7. Which of the following resistor is not used as an integrated resistor?
A. Poly gate resistor
B. Pinched resistor
C. Epitaxial resistor
D. Thin film resistor
Answer: A
Clarification: Except poly gate resistor, other resistors are integrated resistor.
8. Which of the following is not true about diffused resistor?
A. Limitation due to small range of resistance
B. Resistance depends upon surface geometry
C. Resistance depends on diffusion characteristic of material
D. Diffused resistors are non-economical
Answer: D
Clarification: In diffused resistor method, the resistors are very economical as no extra fabrication steps are required.
9. Determine the formula for sheet resistance (Rs).
A. R×L×W
B. R×(L×ρ)/W
C. R×(W/L)
D. R×(W×ρ)/L
Answer: C
Clarification: The formula for sheet resistance of a material of surface dimension L and W is
Rs = R×(W/L).
10. Consider a 52cm×52cm material of uniform resistivity 100Ωm and thickness 3cm. Find the area and resistance of this sheet of material.
A. 16 m2, 1.923 Ω/square
B. 8112 cm2, 1.733 Ω/square
C. 156 cm2, 33.33 Ω/square
D. 901 cm2, 3.333 Ω/square
Answer: C
Clarification: Area = L × t= 52cm×3cm=156 cm2
=> Sheet resistance RS = (ρ×L)/(L×t) = ρ/t = 100 Ω m/3m =33.33 Ω/square.
11. If a 25Ω diffused resistor is to be designed for an emitter resistor, determine the pattern in which it is fabricated?
A. 20mil long by 5mil wide
B. 25mil long by 1mil wide
C. 5mil long by 1mil wide
D. 16mil long by 4mil wide
Answer: B
Clarification: The sheet resistance of n-type diffused resistor is 5Ω/square.
=> L/W=R/RS= 25Ω/5Ω = 5/1
=> 5mil long by 1mil wide.
12. The number of square contained in the integrated resistor by diffused resistor method depend on ratio of
A. ρ/t
B. ρ×L/W
C. W/L×t
D. L/W
Answer: D
Clarification: The number of square contained in the resistor depends on the surface geometry. Which is given by, the ratio L/W is called the aspect ratio of surface geometry.
13. Match the sheet resistance value for the following region in diffused resistor
| 1. Epitaxial Collector region | i. 200Ω/square |
| 2. p-type base region | ii. 1 to 10kΩ/square |
| 3. n-type emitter region | iii. 5Ω/square |
A. 1-I, 2-ii, 3-iii
B. 1-ii, 2-I, 3-iii
C. 1-iii, 2-I, 3-ii
D. 1-iii, 2-ii, 3-i
Answer: B
Clarification: The mentioned values are sheet resistance values for respective diffused resistor.