Effects of Radiation on Semiconductors
The effects of radiation on semiconductors can be classified into the following three categories.
1. SEE (Single Event Effects)
SEE (Single Event Effects) occur when radiation (e.g., protons, neutrons, heavy ions, or gamma rays) ionizes the material as it traverses a device, leading to operational errors in circuitry. If the charge generated by ionization is collected at a sensitive node and is large enough to alter the circuit state, an error occurs. SEE is generally non-destructive and transient; normal operation typically resumes after a reset or power cycle.
SEE is typically evaluated using heavy ions.
SEE Types
- SEU (Single Event Upset): Data bit flip
- SET (Single Event Transient): Temporary voltage pulse
- SEL (Single Event Latch-up): Short-circuit through PNPN path in CMOS structure
- SEB (Single Event Burnout) / SEGR (Single Event Gate Rupture): Destruction of high-power devices
- SEFI (Single Event Functional Interrupt): System-level operational failure
2. TID (Total Ionizing Dose)
Ionizing radiation creates charge that becomes trapped in insulating layers and/or generates defects, gradually shifting device characteristics. This cumulative effect is referred to as TID (Total Ionizing Dose). In CMOS, trapped charge in oxides and interface states drives the dominant behavior.
TID evaluation is typically performed using gamma rays.
Key Impacts
- MOSFET threshold voltage (Vth) shift
- Threshold voltage inversion and increased drain leakage current
- Altered operational characteristics
3. DD (Displacement Damage)
Displacement Damage (DD) affects the semiconductor bulk, whereas TID primarily impacts surfaces and interfaces. DD introduces defects throughout the entire bulk that change electrical, optical, and thermal properties and can degrade performance or functionality. DD evaluation is typically performed using neutrons.
Key Impacts
- Reduced carrier lifetime and mobility
- Increased reverse saturation current in PN diodes
- Overall degradation in performance
Effects of Radiation on Semiconductors
Types of Radiation
Among the many types of radiation, those that typically affect semiconductors include:
Each radiation type interacts differently with semiconductor materials. Click on each item to learn more.