Semiconductors

Question 1

Which is preferred more for transistor manufacturing ? Germanium or Silicon, why?

Answer 1

silicon transistors are preferred over germanium transistors primarily due to their low leakage current, higher breakdown voltage, superior thermal stability, lower cost, and compatibility with silicon dioxide insulators.

Question 2

Which material is under research to replace Silicon, why?

Answer 2

Silicon has physical and quantum-mechanical limitations when scaled down to extremely small sizes (beyond 5 nm nodes). This is leading to research into alternative materials like Gallium Nitride (GaN) and Graphene.

Question 3

What is leakage current?

Answer 3

Leakage current is the small amount of current that flows through the transistor even when it is in the “off” state.

Question 4

What are semiconductors?

Answer 4

Semiconductors are materials whose electrical conductivity is between that of a conductor (like copper) and an insulator (like glass). They are the backbone of electronic devices.

Question 5

Brief note on Silicon and Germanium

Answer 5

Silicon (Si) and Germanium (Ge) are both Group IV elements on the periodic table and have four valence electrons, making them suitable for forming covalent bonds in crystal lattice structures essential for semiconductor properties.

Question 6

What is bandgap?

Answer 6

The bandgap is the energy difference between the valence band (where the electrons are bound to atoms) and the conduction band (where electrons are free to conduct electricity). A larger bandgap makes a semiconductor less conductive at lower temperatures and reduces leakage currents. Silicon: Has a bandgap energy of about 1.12 eV (electron volts) at room temperature.
Germanium: Has a smaller bandgap energy of about 0.66 eV.

Question 7

Give a note on Silicon dioxide

Answer 7

Silicon is the second most abundant element in the Earth’s crust (after oxygen), primarily found in the form of silicon dioxide (sand). Silicon dioxide (SiO₂) forms an excellent insulating layer that is critical in the manufacturing of metal-oxide-semiconductor field-effect transistors (MOSFETs) and other ICs. SiO₂ can be easily grown on silicon wafers, providing a stable and high-quality insulating layer that improves the performance and reliability of transistors.