A follow-up series of simulation experiments have been conducted to study cosmic ray-induced soft errors in CMOS/SOS memories. Devices were tested in beams of krypton and argon ions from the Lawrence Berkeley Laboratory (LBL) 88-inch Cyclotron at energies near 2 MeV/nucleon. The SOS test samples consisted of three versions of the TCS 146, 4K, static memory, constructed with buried contact technology. Small differences in processing have a significant effect on the electrical parameters, and these were observed to correlate with the sensitivity to cosmic ray-induced errors of the three versions. Differences in the probability of flips from 0 Â¿ 1 and 1 Â¿ 0 were observed. These differences are explained in terms of the geometrical details of the memory storage element and the nodal capacitances of the element. The predicted error rate in space was calculated to be 2.6Ã10-9 errors/ day-bit based on the observed critical charge for soft error failure.