Test time optimization of solid-state drives and flash-memory chips during studies of the influence of TID on information preservation

Abstract

Testing the whole volume of memory while estimating the effect of space ionizing radiation on the parameters of flash memory might take long time, which is not acceptable for radiation tests The test time optimization is possible by reducing amount of the tested memory at a cost of predictable loss of accuracy in determining the level of radiation hardness. The nature of data loss under TID irradiation is described. The experimental dependences of number of errors in memory on the relative TID are analyzed based on the test results of nine chip types. A calculated estimate of the amount of memory to test is given, that is sufficient to detect errors in memory cells of the entire solid-state drive for the given detection probability. The experimental data analysis shows that testing 10% of the drive increases the error of the TID hardness level determination no more than 20%. An algorithm for identifying abnormal areas in address space of solid-state drives and flash memory chips is proposed. Knowledge about such areas makes it possible to reasonably choose or further reduce the tested amount of memory.

Keywords

• solid-state drive, flash-memory, radiation hardness, chip, test time optimization, accumulated dose, algorithm for identifying critical areas.