Semiconductor Principles Questions

• Valence electron count and material category Elements with 1, 2, or 3 valence electrons typically behave as what kind of materials in terms of electrical conduction?
• Integrated circuit invention milestone Who demonstrated that more than one transistor could be fabricated on a single piece of semiconductor material, and in which year was this milestone reported?
• Timeline of solid-state device manufacturing Solid-state semiconductor devices first saw significant manufacturing and deployment during which historical period?
• Formation of the depletion region in a p–n junction What physical process primarily creates the depletion region at a freshly formed p–n junction?
• Nature of covalent bonding in semiconductors Electron-pair bonding in a crystal lattice occurs when atoms do which of the following?
• Most significant post–World War II development in electronics Identify the single most impactful advancement in electronics since World War II.
• Materials classification: Are silicon and germanium elemental semiconductors while carbon is generally not classified as a semiconductor at room temperature?
• Historical timeline check: Was the first integrated circuit (IC) invented in 1959, or does the primary invention date trace to 1958?
• Carrier motion in semiconductors: When a DC voltage is applied across a semiconductor, do free electrons drift toward the positive terminal (higher potential) or toward the negative terminal?
• Semiconductor principles — relationship between depletion region width and barrier (built-in) potential In a P–N junction inside a transistor or diode, when the depletion region becomes wider (for example, due to higher built-in potential or added reverse bias), the electrostatic barrier potential across the junction becomes larger. Evaluate this statement.
• Valence electrons of carbon, silicon, and germanium — check the count used in semiconductor bonding Carbon (C), silicon (Si), and germanium (Ge) each have the same number of valence electrons that participate in covalent bonding in crystals. The statement “they have 5 valence electrons” is being evaluated. Decide whether this claim is accurate.
• Historical fact check — year of the first transistor invention (Bell Labs point-contact transistor) Evaluate the statement: “The first transistor was invented in 1938.” Choose whether this claim is correct based on accepted semiconductor history.
• Nature of a covalent bond in semiconductor crystals Evaluate the claim: “A covalent bond is formed when atoms lose valence electrons.” Decide whether this statement accurately describes covalent bonding as found in silicon or germanium lattices.
• Which semiconductor is most widely used and why? (Germanium vs. silicon) Assess the statement: “Germanium is the most widely used semiconductor material because it is stable at high temperatures.” Choose whether this statement is accurate.
• Doping to create n-type semiconductor material — what is actually added? Evaluate the statement: “n-type semiconductor material is created by adding material with electron holes.” Decide whether this description is valid.
• Does the P–N junction act as a barrier to electron flow? (Majority carriers at equilibrium) Evaluate the statement: “The P–N junction is a barrier to electron flow.” Choose the best characterization, considering equilibrium and typical biasing conditions.
• Typical forward junction voltage: silicon vs. germanium devices Evaluate the statement: “The forward voltage drop for a germanium transistor is 0.7 V and for a silicon transistor is 0.3 V.” Decide whether this is accurate for typical small-signal junctions at room temperature.