1. The conductivity of the pure silicon is raised by:
A. Introducing Dopants (impurities)
B. Increasing Pressure
C. Decreasing Temperature
D. Deformation of Lattice
Answer: A
The conductivity of the pure silicon is raised by Introducing Dopants (impurities).
By introducing Dopants free charge carriers increase further increasing the conductivity of silicon.
2. The n-type semiconductor has _______ as the majority carriers.
A. Holes
B. Negative ions
C. Electrons
D. Positive ions
Answer: C
In n-type semiconductors the majority of charge carriers present are electrons.
An n-type semiconductor is an intrinsic semiconductor doped with phosphorus (P), arsenic (As), or antimony (Sb) as an impurity.
Silicon of Group IV has four valence electrons and phosphorus of Group V has five valence electrons
3. The majority of carriers of p-type semiconductors are:
A. Holes
B. Negative ions
C. Electrons
D. Positive ions
Answer: A
The majority of charge carriers of n-type semiconductors are holes.
An n-type semiconductor is an intrinsic semiconductor doped with phosphorus (P), arsenic (As), or antimony (Sb) as an impurity.
Silicon of Group IV has four valence electrons and phosphorus of Group V has five valence electrons
4. The n-MOS transistor is made up of:
A. N-type source, n-type drain and p-type bulk
B. N-type source, p-type drain and p-type bulk
C. P-type source, n-type drain and n-type bulk
D. P-type source, p-type drain and n-type bulk
Answer: A
n-MOS Transistor consists of an n-type source, n-type drain, and p-type bulk.
An n-channel metal-oxide-semiconductor (nMOS) transistor is one in which n-type dopants are used in the gate region (the “channel”). A positive voltage on the gate turns the device on.
5. The oxide layer formed in the MOSFET is:
A. Metal oxide
B. Silicon dioxide
C. Poly Silicon oxide
D. Oxides of Non-metals
Answer: B
Silicon Dioxide (Commonly called glass) is the insulating oxide layer formed in MOSFET.
Silicon dioxide (SiO2), also known as silica, is a natural compound made of two of the earth’s most abundant materials: silicon (Si) and oxygen (O2).
6. The drain current is varied by:
A. Gate to source voltage
B. Gate current
C. Source Voltage
D. None of the mentioned
Answer: A
The Gate to Source voltage acts as input which varies the drain current.
The drain is the terminal through which the majority of charge carriers exit from the FET.
7. The low voltage on the gate of p-MOSFET forms:
A. Channel of negative carriers
B. Channel is not formed
C. Channel is clipped
D. Channel of positive carriers
Answer: D
For a p-MOS low gate voltage forms a conducting channel of positive carriers.
As long as the gate control voltage, VC is LOW (or negative), the PMOS transistor will pass the input voltage to the output.
If it is HIGH, the PMOS transistor is turned “OFF”, and the output terminal is disconnected from the input.
8. The n-MOSFET is working as accumulation mode when:
A. Gate is applied with positive voltage
B. Gate is grounded
C. Gate is applied with negative voltage
D. Gate is connected to the source
Answer: C
When the negative voltage is applied to the gate, there develops a presence of a negative charge on the gate. The mobile positively charged holes are attracted to the region beneath the gate. This explains the formation of the accumulation mode.
9. The current through the n-MOS transistor will flow when:
A. Vgs > Vtreshold, Vds=0
B. Vgd < Vtreshold, Vds=0
C. Vgs > Vtreshold, Vds>0
D. Vgd > Vtreshold, Vds<0
Answer: C
The current flows through the n-MOS transistor when Vgs > Vtreshold, Vds>0.
10. The p-MOS Transistor is said to be in Saturation mode when:
A. Vdsp > Vgsp – Vtp
B. Vgsp < Vdsp –Vtp
C. Vgsp > Vtp
D. Vdsp < Vgsp – Vtp
Answer: D
The pMOS transistor is in Saturation mode when Vdsp < Vgsp – Vtp and Vgsp < Vtp.
