Transistor Aging

Niranjan Soundararajan

Aging

TimelineClock period

Fails!!

Start of lifetime

Transistors do age… like humans

• Transistors slow down over time

• Rate of aging very related to stress

• Similarities exist in the cause and effect of aging

Mortality rate comparison

Process Variation - Systematic: You are as good as your friends

Different Aging Phenomena• NBTI– Transistor holds same data for long periods– “All work and no play”

• HCE– Related to amount of switching– Moving back and forth between jobs

• Oxide Breakdown– Breakdown of gate-oxide between semi-conductors

slowly over time• Electro-Migration– Electron flow in same direction– Blood flow

Decreasing aging effects• Stress reduction mechanisms

– Meditation – Decrease temperature for transistors– Load-balancing

• Facelift – “Transistor Aging” related paper

• Defect tolerance

• Monitoring– Health periodically– Sensors on-chip to identify stressed transistors