Unit-3 CFM

Which of the following statements is true about intrinsic semiconductors?

• Intrinsic semiconductors are pure materials without any significant dopants

• Intrinsic semiconductors have high conductivity at room temperature

• Intrinsic semiconductors are always metallic in nature

• Intrinsic semiconductors have excess free electrons due to doping

The electrical conductivity of a P-type semiconductor is primarily due to

• Free electrons

• Holes

• Neutrons

• Protons

In the Czochralski method, what is the role of the seed crystal?

• It is used to initiate the crystal growth process.

• It supplies the material for crystal growth.

• It controls the temperature of the process

• It melts the mater

In the Czochralski method, what is the temperature range typically required to melt the semiconductor material (e.g., silicon)?

• 500°C- to 600°C

• 3000°C to 3500°C

• 1200°C to 1500°C

• 2000°C to 2200°C

In the Czochralski process, what happens as the seed crystal is slowly withdrawn from the melt?

• The crystal melts.

• The crystal cools and solidifies to form a larger single crystal

• The crystal gets dissolved into the melt

• The crystal forms multiple small crystals.

In the Czochralski method, which of the following factors can be controlled to influence the size of the crystal?

• The temperature of the melt

• The pulling rate of the seed crystal

• The rotation speed of the seed crystal

• All of the above

Which of the following is a significant advantage of the Float Zone method over the Czochralski method?

• It uses a crucible to melt the material.

• It produces smaller, less pure crystals

• It avoids contamination from a crucible, producing higher purity crystals

• It can only be used for metals, not semiconductors.

In the Czochralski process, what happens as the seed crystal is slowly withdrawn from the melt?

• The crystal melts.

• The crystal cools and solidifies to form a larger single crystal

• The crystal gets dissolved into the melt

• The crystal forms multiple small crystals.

Which of the following is a key limitation of the Float Zone method?

• It requires a high-temperature crucible

• It can only be used for small crystals

• It is difficult to scale for large diameter crystals.

• It is only suitable for metals.

What is the main application of Gallium Arsenide (GaAs) in electronics?

• Higher electron mobility

• Lower thermal conductivity

• Higher bandgap energy

• Higher melting point