Locating radiation sensitive zones of integrated circuits using an ion-microprobe

An imaging technique is described which produces micron-resolution maps of the single-event upset sensitive regions of integrated circuits during ion-irradiation. From these "upset images" the identity and size of a circuit's upset-prone components can be directly determined. Utilizing a scanning ion-microprobe, the imaging technique selectively exposes the functional units of an integrated circuit (e.g. transistor drains, gates) and immediately measures the effect of high-energy ion strikes on circuit performance. Such detailed spatial characterization provides a precision diagnostic technique with which the study of single-event upset processes in integrated circuits becomes more efficient

Microbeam mapping of single event latchups and single event upsets in CMOS SRAMs

The first simultaneous microbeam mapping of single event upset (SEU) and latchup (SEL) in the CMOS RAM HR165162 is presented. We found that the shapes of the sensitive areas depend on VDD, on the ions being used and on the site on the chip being hit by the ion. In particular, we found SEL sensitive sites close to the main power supply lines between the memory-bit-arrays by detecting the accompanying current surge. All these SELs were also accompanied by bit-flips elsewhere in the memory (which we call "indirect" SEUs in contrast to the well known SEUs induced in the hit memory cell only). When identical SEL sensitive sites were hit farther away from the supply lines only indirect SEL sensitive sites could be detected. We interpret these events as "latent" latchups in contrast to the "classical" ones detected by their induced current surge. These latent SELs were probably decoupled from the main supply lines by the high resistivity of the local supply lines

Heavy ion microscopy of single event upsets in CMOS SRAMs

The single event upset (SEU) imaging has been applied at the GSI heavy ion microprobe to determine the sensitivity of integrated circuits (IC) to heavy ion irradiation. This method offers the possibilty to directly image those parts of an IC which are sensitive to ion-induced malfunctions. By a 3-dimensional simulation of charge collection across p-n-micro-junctions we can predict SEU cross-sections. For a MHS65 162 2k x 8bit CMOS SRAM we found two regions per bit with different sensitivity and measured a total cross-section of (71 +/- 18)µm² for a bitflip per cell and simulated 60µm² with an argon beam of 1.4 Mev/nucl. (LET of 19.7 MeV/mg/cm²)

Hyperglycemia and adverse pregnancy outcome (HAPO) study: Preeclampsia

OBJECTIVE: The purpose of this study was to examine associations of fasting C-peptide, body mass index (BMI), and maternal glucose with the risk of preeclampsia in a multicenter multinational study