This set of VLSI Multiple Choice Questions & Answers (MCQs) focuses on “Stick Diagram”.
1. Stick diagrams are those which convey layer information through
Explanation: Stick diagrams are those which convey layer information through color codes. Thickness is not considered in this stick diagram representation.
2. Which color is used for n-diffusion?
Explanation: Green color is used to show the presence of n-diffusion layer. The n-type diffusion will dope the source or drain region in the p-well region.
3. Which color is used for implant?
Explanation: Yellow color is used to represent implant layer.
4. Which color is used for contact areas?
Explanation: Black color is used to represent contact areas. This is the part where two different touch or cross each other.
5. Which color is used for polysilicon?
Explanation: Red is used to represent polysilicon layers. It is a semi-conductor like material and is a hyper pure form of silicon.
6. Which color is used for polysilicon 2?
Explanation: Orange color is used to represent polysilicon-2 layer.
7. Which color is used for buried contact?
Explanation: Brown color is used to represent buried contact. Buried contact is most widely used, subject to fewer design rule restrictions and are smaller in area.
8. n and p transistors are separated by using
a) differentiation line
b) separation line
c) demarcation line
d) black line
Explanation: Demarcation line separates n and p transistors. Demarcation line is similar to dotted line in brown.
9. _______ layer should be over ______ layer
a) ntype, polysilicon
b) polysilicon, ntype
Explanation: Polysilicon layer should be over n-type layer. This is the standard pattern used in stick diagram representation.
Explanation: nMOS depletion mode transistor can be represented by using polysilicon over ntype layer and with an implant.
11. Implant is represented using
a) black, dark line
b) black, dotted line
c) yellow, dark line
d) yellow, dotted line
Explanation: Implant is represented using yellow color dotted lines. It is drawn in the middle of the nMOS or pMOS whereever the implant is used.
12. Stick diagram gives the position of placement of the element.
Explanation: Stick diagram does not show exact placement of components, transistor length, wire length and width, tub boundaries etc.
13. When two or more cuts of same type cross or touch each other, that represents
a) contact cut
b) electrical contact
c) like contact
d) cross contact
Explanation: When two or more sticks of same type cross or touch each other, then that forms a contact called electrical contact.
Sanfoundry Global Education & Learning Series – VLSI.
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