16 Questions
What is the effect of P-well doping concentration and depth on CMOS fabrication?
Threshold voltage
What type of light is used to expose the photoresist layer in CMOS fabrication?
Ultraviolet light
What is the characteristic of an enhancement MOSFET?
Widely used because of easy in its fabrication
What is the method used to form N-well in CMOS fabrication?
Diffusion
What is the relationship between (W/L)P and (W/L)N for a symmetric CMOS inverter?
(W/L)P = 3(W/L)N
What is used to reduce the resistivity of poly silicon?
Doping impurities
How is nMOS inverter represented?
vlsi-questions-answers-nmos-inverter-q6b
Why is MOSFET widely used in digital circuits?
All of the above
What is CMOS technology used in developing?
All of the mentioned
How is N-well formed in CMOS fabrication?
Diffusion
What is a characteristic of CMOS technology?
High noise margin
What is the intrinsic gain of a MOSFET with Vgs= 2V, Vtn =1V, Id=1mA, λ =0.01V-1?
100
Are nMOS and pMOS integrated in the same substrate in CMOS fabrication?
True
What is the primary function of inverters in digital circuits?
All of the mentioned
What is the type of transistor used as a load in a basic inverter circuit?
Depletion mode
What is the correct order of the design flow of a VLSI system?
1-2-3-4
Study Notes
CMOS Technology
- CMOS technology is used in developing microprocessors, microcontrollers, and digital logic circuits.
- N-well is formed by diffusion.
CMOS Characteristics
- CMOS has high noise margin and high packing density.
- CMOS has low power dissipation.
MOSFET
- For a MOSFET with Vgs= 2V, Vtn =1v, Id=1mA, and λ =0.01v-1, its intrinsic gain is 200.
- In a MOSFET, Vgs is the voltage between the gate and source, and Vtn is the threshold voltage.
Inverter Circuits
- Inverters are essential for sequential circuits.
- In a basic inverter circuit, the source is connected to ground.
- In an inverter circuit, depletion mode transistors are used as load.
- In nMOS inverter configuration, depletion mode device is called as pull down.
VLSI Design Flow
- The design flow of VLSI system is: architecture design, market requirement, logic design, and HDL coding.
CMOS Fabrication
- In CMOS fabrication, nMOS and pMOS are integrated in the same substrate.
- P-well is created on an n-substrate.
- Photoresist layer is formed using light-sensitive polymer and is exposed to ultraviolet light.
- P-well doping concentration and depth will affect the threshold voltage.
CMOS Circuits
- CMOS circuits are good and better because they have low power consumption, less noise, and take up a small amount of space on a chip.
- The enhancement MOSFET is widely used because of its ease of fabrication.
- Mobility depends on the transverse electric field.
- For a symmetric CMOS inverter, (W/L)
P= 2.5(W/L)N.
Poly Silicon
- Doping impurities is used to reduce the resistivity of poly silicon.
NMOS Inverter
- An nMOS inverter is represented by a specific circuit diagram.
- A CMOS inverter has four distinct modes of operation.
DIBL
- DIBL (Drain-Induced Barrier Lowering) has subthreshold conduction, gate leakage, and junction leakage as sources of leakage.
Test your knowledge of CMOS technology, microprocessors, and MOSFETs in this quiz. Covers topics such as digital logic circuits, noise margin, and power dissipation.
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