Application of 2D Walsh-Hadamard transform in SRAM upset bitmaps processing

Upset bitmaps distribution features in SRAM arrays exposed by various types of pulsed ionizing radiation (X-rays, n-γ, laser-accelerated protons) were analyzed by experimental data processing with 2D Walsh-Hadamard transform, i.e. expansion of orthogonal rectangle functions on closed set basis. Using such processing with comparison to expansion on 1D Fourier or Walsh-Hadamard transform allows one to detect additional regularities in upset distribution. The presence of these regularities can be explained by voltage dropdown across integrated circuit voltage supply buses arising under pulsed radiation exposure as a result of dose rate effects. The “stripe-like” upset bitmap is explicitly observed under the pulsed X-ray exposure. In the case of pulsed complex n-γ (fission neutrons) and laser-accelerated protons exposure the dose rate effects significance and therefore the presence of any regularities in upset bitmaps are strongly device-specific. A quantitative criterion was introduced on basis of 2D Walsh-Hadamard amplitude spectra's statistical examination permitting to pick out upset bitmaps with regularities even for visually uniform upset bitmaps.