20+ Top Metal-Semiconductor Contacts MCQ with Answers
In a metal-semiconductor contact, the Fermi level of the metal is __________ the Fermi level of the semiconductor.
a) Lower than
b) Higher than
c) Equal to
Answer: c
Hint: At equilibrium, the Fermi levels of both materials are aligned.
The barrier height at a metal-semiconductor contact depends on:
a) Work function of the metal
b) Bandgap of the semiconductor
c) Doping concentration of the semiconductor
Answer: a
Hint: The work function of the metal determines the barrier height.
Schottky diodes are formed by a metal-semiconductor contact with:
a) High barrier height
b) Low barrier height
c) No barrier
Answer: a
Hint: Schottky diodes have a high barrier at the metal-semiconductor junction.
Ohmic contacts are characterized by:
a) High resistance
b) Low resistance
c) Rectifying behavior
Answer: b
Hint: Ohmic contacts have low resistance and allow easy current flow.
The depletion region in a metal-semiconductor contact is caused by:
a) Majority carriers in the metal
b) Minority carriers in the metal
c) Majority carriers in the semiconductor
Answer: b
Hint: Minority carriers in the metal create the depletion region.
In an ideal metal-semiconductor contact, the barrier height is:
a) Zero
b) Maximum
c) Minimum
Answer: a
Hint: An ideal contact has no barrier height.
The majority of carriers in the metal region of a metal-semiconductor contact are:
a) Electrons
b) Holes
c) Protons
Answer: a
Hint: Metals have an abundance of free electrons.
What is the process by which charged particles move through a material in response to an electric field?
A) Electromagnetic Radiation
B) Conduction
C) Insulation
D) Refraction
Answer: B
Hint: This process occurs in conductive materials, allowing the flow of charge.
In which direction do positive charges move in a typical electric circuit?
A) Towards the positive terminal of the voltage source
B) Towards the negative terminal of the voltage source
C) Randomly in all directions
D) Away from any voltage source
Answer: A
Hint: Positive charges are attracted towards the terminal with higher potential.
What type of current transport process occurs in gases or vacuum and does not require a physical medium?
A) Conduction
B) Induction
C) Convection
D) Displacement of current
Answer: D
Hint: This concept is related to one of Maxwell’s equations and is used in electromagnetic wave propagation.
Which of the following materials typically exhibits the highest electrical conductivity?
A) Insulator
B) Semiconductor
C) Superconductor
D) Dielectric
Answer: C
Hint: Superconductors allow the flow of electric current without any resistance.
What is the process by which charge carriers collide with atoms or impurities, leading to an increase in resistance?
A) Electromigration
B) Joule Heating
C) Scattering
D) Polarization
Answer: C
Hint: This process contributes to the resistivity of materials.
Which current transport process involves the movement of charged ions in a solution, driven by an electric field?
A) Ionic Conduction
B) Dielectric Breakdown
C) Tunneling
D) Quantum Confinement
Answer: A
Hint: This process is essential in electrolytic cells and batteries.
What phenomenon describes the tendency of certain materials to exhibit zero resistance at very low temperatures?
A) Joule-Thomson Effect
B) Thermoelectric Effect
C) Superconductivity
D) Photoelectric Effect
Answer: C
Hint: This property allows for lossless transmission of electric current.
What is an Ohmic contact?
A) A type of electrical conductor with high resistance
B) A type of electrical conductor with low resistance
C) A semiconductor material with no resistance
D) A type of insulation material
Answer: B
Hint: Ohmic contacts exhibit linear current-voltage characteristics and low resistance.
What happens to the resistance of an Ohmic contact as the temperature increases?
A) It increases
B) It decreases
C) It remains constant
D) It becomes negative
Answer: A
Hint: Ohmic contacts follow the relationship R = ρ * A / L, where ρ is the resistivity and increases with temperature.
What type of electrical behavior do Ohmic contacts display?
A) Non-linear
B) Exponential
C) Ohmic (linear)
D) Discontinuous
Answer: C
Hint: Ohmic contacts show linear current-voltage characteristics.
Which material is commonly used for creating Ohmic contacts to semiconductors?
A) Insulators
B) Superconductors
C) Metals
D) Dielectrics
Answer: C
Hint: Metals are good choices for creating Ohmic contacts due to their low resistance.
What is the primary purpose of an Ohmic contact in a semiconductor device?
A) To provide insulation
B) To increase resistance
C) To improve the current flow
D) To prevent electron flow
Answer: C
Hint: Ohmic contacts ensure efficient current injection and extraction in semiconductor devices.
Which of the following IV (current-voltage) curves represents an Ohmic contact?
A) Exponential curve
B) Hyperbolic curve
C) Parabolic curve
D) Linear curve
Answer: D
Hint: Ohmic contacts display a straight-line relationship between current and voltage.
When does an Ohmic contact behave like an ideal conductor?
A) At very high temperatures
B) At very low temperatures
C) At room temperature
D) At absolute zero temperature
Answer: D
Hint: Ideal Ohmic behavior is observed at absolute zero temperature.
In an Ohmic contact, what happens when the voltage is zero?
A) Current becomes zero
B) Resistance becomes infinite
C) Current becomes infinite
D) Resistance becomes zero
Answer: A
Hint: Ohmic contacts exhibit current flow even at zero voltage.
Which of the following statements about Ohmic contacts is true?
A) They only work in vacuum conditions
B) They can be formed with any material
C) They have a negative temperature coefficient
D) They cannot be used in electronic devices
Answer: B
Hint: Ohmic contacts can be formed using various conductive materials.
What is the term used to describe the deviation from Ohmic behavior in a contact?
A) Insulation effect
B) Non-linearity
C) Non-Ohmic effect
D) Breakdown effect
Answer: C
Hint: Non-Ohmic effect refers to the departure from linear current-voltage characteristics in a contact
Which current transport process involves the movement of electrons from one energy band to another in a semiconductor?
A) Drift
B) Diffusion
C) Avalanche Breakdown
D) Band-to-Band Transition
Answer: D
Hint: This process plays a crucial role in the operation of diodes and transistors
What is the process by which electric charges accumulate on the surface of an object due to the redistribution of charges?
A) Capacitance
B) Electrostatic Discharge
C) Charging by Induction
D) Dielectric Polarization
Answer: C
Hint: This process is commonly used in electrostatic experiments.
Which current transport process occurs in fluids or gases due to the movement of charged particles in response to temperature gradients?
A) Thermionic Emission
B) Conduction
C) Convection
D) Tunneling
Answer: C
Hint: This process is associated with heat transfer in fluids
The type of metal-semiconductor contact used in Schottky diodes is:
a) Ohmic contact
b) Non-ohmic contact
Answer: b
Hint: Schottky diodes use non-ohmic contacts with high barrier heights.
The current-voltage characteristics of an ideal metal-semiconductor contact are:
a) Linear
b) Exponential
c) Non-linear
Answer: a
Hint: Ideal contacts have linear current-voltage characteristics.
The forward voltage drop in a Schottky diode is due to:
a) Majority carrier conduction
b) Minority carrier conduction
c) Tunneling effect
Answer: b
Hint: In forward bias, minority carriers dominate conduction in Schottky diodes.
The work function of a metal is a measure of its:
a) Barrier height
b) Conductivity
c) Electronegativity
Answer: a
Hint: The work function determines the barrier height at the metal-semiconductor junction.
The breakdown voltage in a Schottky diode is determined by:
a) Work function of the metal
b) Doping concentration of the semiconductor
c) Bandgap of the semiconductor
Answer: b
Hint: Doping concentration influences breakdown voltage in Schottky diodes.
The contact resistance in a metal-semiconductor contact depends on:
a) Barrier height
b) Doping concentration
c) Temperature
Answer: b
Hint: Contact resistance is affected by doping concentration in the semiconductor.
The forward voltage drop in an ideal metal-semiconductor contact is:
a) Zero
b) Maximum
c) Minimum
Answer: a
Hint: In an ideal contact, there is no forward voltage drop.
In a Schottky diode, the barrier height can be reduced by:
a) Increasing doping concentration
b) Decreasing doping concentration
c) Changing the metal used
Answer: a
Hint: Higher doping concentration reduces the barrier height in Schottky diodes.
The rectification property in a metal-semiconductor contact is due to:
a) Majority carriers
b) Minority carriers
c) Both majority and minority carriers
Answer: b
Hint: Rectification is caused by minority carrier conduction.
The depletion region width in a metal-semiconductor contact is influenced by:
a) Applied voltage
b) Barrier height
c) Doping concentration
Answer: a
Hint: The width of the depletion region changes with the applied voltage.
The energy band diagram at a metal-semiconductor contact shows:
a) Flat band condition
b) Band bending
c) No change in the band structure
Answer: b
Hint: Band bending occurs at the metal-semiconductor interface.
The reverse leakage current in a Schottky diode is due to:
a) Majority carriers
b) Minority carriers
c) Both majority and minority carriers
Answer: a
Hint: In reverse bias, the majority of carriers contribute to leakage current.
The barrier height in a metal-semiconductor contact can be modified by:
a) Changing the semiconductor material
b) Changing the metal material
c) Both changing semiconductor and metal materials
Answer: c
Hint: The barrier height can be adjusted by altering the materials used.
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