Which statement about semiconductor device reliability is generally correct when compared to electromechanical components and typical failure patterns over a product life cycle?

Introduction / Context:
This question targets reliability engineering concepts, especially the bath-tub curve for electronic components. It asks which statement aligns with observed failure distributions for semiconductors across early life, useful life, and wear-out phases.

Given Data / Assumptions:

• Semiconductor devices are solid-state with no moving parts.
• Electromechanical devices include relays, switches, and motors that have wear from mechanical motion.
• MTBF represents expected time between failures during the useful life phase.

Concept / Approach:
Semiconductors typically show early failures due to latent manufacturing defects. Burn-in screens out weak units, reducing early failure rates. During the long useful life, failure rate is low and MTBF is high. Statements must be checked against this pattern.

Step-by-Step Solution:

Verification / Alternative check:
Industry practice uses burn-in and accelerated life testing to remove weak units, confirming the brief early failure window, followed by a long low-failure plateau.

Why Other Options Are Wrong:

• are less reliable than electromechanical components: generally false; solid-state devices usually exhibit higher reliability.
• usually have a very short MTBF: false; MTBF is typically long in the useful life phase.
• All of the above: cannot be correct because the first two statements are false.
• None of the above: incorrect because the infant mortality statement is correct.

Common Pitfalls:
Assuming constant failure rate across life, confusing MTBF with warranty length, and ignoring screening processes that remove weak devices.

Final Answer:
have a very short infant mortality period