Are PMOS and NMOS circuit implementations “identical except for voltage polarity”? Consider common digital design practices and device physics to evaluate this statement.

Introduction / Context:
PMOS and NMOS are complementary device types with different carrier mobilities and threshold behaviors. While logical functions can be mirrored with polarity changes, practical circuit implementations are not truly identical due to performance and device-physics differences.

Given Data / Assumptions:

• Electron mobility (nMOS) exceeds hole mobility (pMOS), affecting conductivity for the same geometry.
• Historic PMOS and NMOS families used different load strategies and had different speed/power characteristics.
• In CMOS, pull-up (pMOS) and pull-down (nMOS) networks are complementary but sized differently.

Concept / Approach:
The statement claims identity except for voltage polarity. In reality, even if the logic function can be inverted or mirrored, designers must compensate for mobility differences, threshold voltages, body effects, and leakage by sizing devices and choosing topologies appropriately. Thus, the implementations are not identical.

Step-by-Step Solution:

Verification / Alternative check:
Process and standard-cell documentation show different width/length recommendations for pMOS and nMOS to balance drive strength and timing.

Why Other Options Are Wrong:

Common Pitfalls:
Equating symbolic Boolean duality with physical identity; forgetting that timing symmetry requires unequal device sizing.

Final Answer:
Incorrect