Soft Error Dependence on Feature Size

This paper reports on an experimental effort to determaine the dependence of critical charge, Qc on feature size (channel length L), in CMOS/SOS rad-hard 16K memories. The Single Event Upset (SEU) tests were conducted at the Berkeley 88" cyclotron, using krypton ions of 138 MeV and argon ions of 85 MeV with LET values of 40 and 18.3 MeV-cm2/mg, respectively. A subsequent second test was conducted at the Oak Ridge Van de Graaff. Gold ions of 591 MeV with an LET = 88 MeV-cm2/mg were used to test samples from the same lots as in the Berkeley test. Results showed that Qc ¿ L1.6 ±0.2.