MOS Transistors MCQ : Here you will find MCQ Questions related to "MOS Transistors" in VLSI. These MOS Transistors MCQ Questions Will help you to improve your VLSI knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations.
How many layers MOS structure contains?
Explanation: MOS structure contains three layers : The Metal Gate Electrode, The Insulating Oxide Layer (SiO2), P – type Semiconductor (Substrate)
The thickness of dielectric material (SiO2) is usually between ?
A. 10 nm and 50 nm
B. 15 nm and 50 nm
C. 5 nm and 50 nm
D. 20 nm and 50 nm
Explanation: MOS structure forms a capacitor, with gate and substrate are as two plates and oxide layer as the dielectric material. The thickness of dielectric material (SiO2) is usually between 10 nm and 50 nm.
Which of the following is correct formula of Mass Action Law?
Explanation: Concentration of carrier in semiconductor material is always following the Mass Action Law. Mass Action Law is given by : n.p=(n^2)i
In Mass Action Law, n stands for?
A. n is carrier concentration of holes
B. n is intrinsic carrier concentration of Silicon
C. n is carrier concentration of electrons
D. All of the above
Explanation: n is carrier concentration of electrons
The band gap between conduction band and valance band is?
Explanation: The band gap between conduction band and valance band is 1.1eV.
The potential difference between conduction band and free space is called?
B. fermi potential
C. work function
D. electron affinity
Explanation: The potential difference between conduction band and free space is called electron affinity and is denoted by qx.
nMOS devices are formed in ____________
A. p-type substrate of high doping level
B. n-type substrate of low doping level
C. p-type substrate of moderate doping level
D. n-type substrate of high doping level
Explanation: nMOS devices are formed in a p-type substrate of moderate doping level. nMOS devices have higher mobility and is cheaper.
Source and drain in nMOS device are isolated by ____________
A. a single diode
B. two diodes
C. three diodes
D. four diodes
Explanation: The source and drain regions are formed by diffusing n-type impurity, it gives rise to depletion region which extend in more lightly doped p-region. Thus Source and drain in an nMOS device are isolated by two diodes.
In MOS transistors _______________ is used for their gate.
Explanation: In MOS transistors, polycrystalline silicon is used for their gate region instead of metal. Polysilicon gates have replaced all other older devices.
The gate region consists of ____________
A. insulating layer
B. lower metal layer
C. p type layer
D. conducting layer
Explanation: The gate region is a sandwich consisting of semiconductor layer, an insulating layer and an upper metal layer.