Irradiation Standard
Military test standards define uniform environmental tests for microelectronic devices to ensure their suitability for military and aerospace applications. The procedure known as mil-std-883 method 1017 outlines the specific protocol for conducting neutron irradiation testing on these components. This test assesses the susceptibility of integrated circuits and discrete semiconductors to displacement damage caused by neutron exposure.
It establishes the required neutron fluence levels, the beam characteristics, and the dosimetry measurements necessary for a valid test. Hardware qualification programs rely on this method to verify that electronics can survive the nuclear or space radiation environments of their intended missions.
Damage Mechanism
High-energy neutrons collide with the silicon atoms in the semiconductor lattice, displacing them from their normal lattice sites and creating permanent defects. When executing mil-std-883 method 1017, the test focuses on these displacement damage effects rather than surface ionization. This structural degradation reduces carrier lifetime, increases leakage currents, and decreases the gain of bipolar transistors.
Device Characterization
Pre-irradiation and post-irradiation electrical measurements are performed to quantify the extent of parameter degradation. The implementation of mil-std-883 method 1017 requires measuring critical parameters like supply currents, switching speeds, and threshold voltages. If these parameters drift beyond the pre-defined limits after the exposure, the batch must be rejected for high-reliability applications.
Test Facility
Nuclear reactors or specialized neutron generators are utilized to produce the controlled neutron beam required for the evaluation. Compliance with mil-std-883 method 1017 demands that the neutron spectrum and the total fluence are measured using calibrated foil activation or active dosimetry. These rigorous measurement steps guarantee that the radiation dose applied during testing is accurate and traceably documented.
