Radiation dependence of inverter propagation delay from timing sampler measurements

• Published in: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (USA) Vol. 36; no. 6; pp. 1981 - 1989
• Main Authors: Buehler, M.G., Blaes, B.R., Lin, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Legacy CDMS IEEE 01.12.1989
• Subjects: 440200 - Radiation Effects on Instrument Components, Instruments, or Electronic Systems; CMOS technology; Cobalt; ELECTRICAL EQUIPMENT; Electronics And Electrical Engineering; FABRICATION; HARDENING; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; INVERTERS; MATERIALS; MOS TRANSISTORS; MOSFET circuits; N-TYPE CONDUCTORS; PHYSICAL RADIATION EFFECTS; Propagation delay; Radiation detectors; RADIATION EFFECTS; RADIATION HARDENING; Ring oscillators; Semiconductor device measurement; Semiconductor device modeling; SEMICONDUCTOR DEVICES; SEMICONDUCTOR MATERIALS; SENSITIVITY ANALYSIS; Timing; TRANSISTORS; TRAPPING
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/23.45395

A timing sampler consisting of 14 four-stage inverter-pair chains with different load capacitances was fabricated in 1.6- mu m n-well CMOS and irradiated with cobalt-60 at 10 rad(Si)/s. For this CMOS process the measured results indicate that the rising delay increases by about 2.2 ns/Mrad(Si) and the falling delay increase is very small, i.e., less than 300 ps/Mrad(Si). The amount of radiation-induced delay depends on the size of the load capacitance. The maximum value observed for this effect was 5.65 ns/pF-Mrad(Si). Using a sensitivity analysis, the sensitivity of the rising delay to radiation can be explained by a simple timing model and the radiation sensitivity of DC MOSFET parameters. This same approach could not explain the insensitivity of the falling delay to radiation. This may be due to a failure of the timing model and/or trapping effects.< >