Integrated Circuits Questions and Answers
Q1. What is an IC?
An integrated circuit (IC) is one in which all active and passive components such as transistor, diodes, resistors, capacitors etc. are automatically part of a small semiconductor chip.
Q2. Why are ICs so cheap?
ICs are so cheap because of simultaneous production of hundreds of similar circuits on a small semiconductor wafer.
Q3. Why do ICs need small power for their operation?
ICs need small power due to their small size.
Q4. Why are ICs more reliable than discrete circuits?
ICs are more reliable because of elimination of soldered joints and need for fewer interconnections.
Q5. What are the advantages of ICs over discrete component circuits?
The advantages of IC’s over discrete component circuits are extremely small size, very small weight, very low cost, lower power consumption, more reliability, easy replacement, increased operating speed, close matching, improved functional performance, suitability for small signal operation etc.
Q6. What are the important IC technologies used?
IC technologies used are monolithic, thin- and thick-flim , and hybrid or multichip.
Q7. What is monolithic IC?
A monolithic IC is one in which all circuit components and their interconnections are formed on a single thin wafer, called the substrate.
Q8. Why is SIO2 layer formed over the entire surface in a monolithic IC?
SIO2 layer is formed over the entire surface so as to prevent the contamination of the epitaxial layer.
Q9. How is SIO2 layer formed in a monolithic IC?
The SIO2 layer is grown by exposing the epitaxial layer to an oxygen atmosphere to about 1,000oC.
Q10. In ICs the substrate is not employed as collector. Why?
If in ICs the substrate is employed as collector, all transistors fabricated on one substrate would have their collectors connected together.
Q11. Why is the diffusion technique of formation of resistor most widely used?
The diffused resistors can be processed while diffusing transistors, so the diffusion technique is the cheapest and, therefore, is most widely used.
Q12. Why is the plastic DIP IC package most widely used?
The plastic dual-in-line package is much cheaper than other types of packages and is, therefore, most widely used.