A portable planar Sr-90 irradiation setup for total dose testing of electronic devices

A portable irradiation setup using a planar Sr-90 source was built and characterized. The dose at various positions in this facility was experimentally determined with an accuracy better than 10%, as required by conventional standards. A calculation method was employed to evaluate both the energy spectrum and the dose-depth curve of the source. The agreement with experiment for depths larger than 0.5 mm Al is good. The RADFET dosimeter seems to give the best estimate for the surface dose. Irradiation of commercial delidded devices indicates that the planar β source gives results in excellent agreement with those obtained by Co-60 (γ) irradiations at equivalent doses. To avoid inaccuracy in dose estimation, the use of an Al (or other material) foil 0.1-0.15 g/cm² thick between the source and delidded device was investigated. The portable irradiation setup can be very useful for irradiation of delidded devices at the prime or hybrid manufacturer or application specific integrated circuit (ASIC) user, permitting the use of their testing systems