Question: 11 -

Sheet resistance for 1 mm thick Si wafer with phosphorous doping of 10¹⁶ cm^-3 and boron doping of 2*10¹⁶ cm^-3 is

200 Ω^-2

300 Ω^-2

240 Ω^-2

350 Ω^-2

Answer:

240 Ω^-2

Solution not available.

Question: 12 -

Almost all resistor are made in a monolithic integrated circuit

during the collector diffusion

during the emitter diffusion

during the base diffusion

while growing the exitaxial layer

Answer:

during the emitter diffusion

Solution:

All resistor are made during emitter diffusion

Question: 13 -

Consider the following statements :-

The temperature dependance of resistivity of a sample of N-type silicon is based upon carrier mobility variations with temperature because

(i) The resistivity of silicon increases with temperature

(ii) The mobility decreases with temperature

(iii) The carrier concentration increases with temperature

(iv) The resistivity of silicon decreases with temperature 

Which of these statements are correct? 

ii and i

iii and iv

ii , i and iii

ii , iii and iv

Answer:

ii , i and iii

Solution:

Mobility decreases with temperature , with temperature more electron-holes pairs generated so conductivity decreases

Question: 14 -

Main purpose of metallization process is

Interconnection of circuit element

Supply bonding surface for chip modeling

Act as heat sink

Preventing chip from oxidation

Answer:

Interconnection of circuit element

Solution not available.

Question: 15 -

The basic function of buried n⁺ layer in an n-p-n transistor fabricated in IC is to

Reduce the magnitude of the base spreading resistance

Reduce the base width of the transistor

increase the gain of the transistor

Reduce the collector series resistance

Answer:

Reduce the collector series resistance

Solution:

Buried n⁺ layer reduces collector resistance