nickel contamination
**Nickel Contamination** in semiconductor processing refers to unwanted Ni atoms that diffuse rapidly in silicon, creating deep-level traps that degrade device performance and reliability.
## What Is Nickel Contamination?
- **Sources**: Plating baths, stainless steel equipment, sputtering targets
- **Behavior**: Fast interstitial diffuser in Si (D ≈ 10⁻⁴ cm²/s at 1000°C)
- **Effect**: Mid-gap trap states, reduced carrier lifetime
- **Detection**: TXRF, SIMS, DLTS
## Why Nickel Contamination Matters
Nickel is one of the fastest diffusing metals in silicon. Even low surface contamination distributes throughout the wafer during thermal processing.
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**Prevention and Detection**:
| Method | Application |
|--------|-------------|
| TXRF | Surface detection (<10¹⁰ at/cm²) |
| DLTS | Trap level identification |
| SPV | Lifetime degradation mapping |
| Gettering | Backside or intrinsic gettering |