Field oxide inversion effects in irradiated CMOS devices

Conference · Mon Mar 01 00:00:00 EST 1976

DOI:https://doi.org/10.1109/TNS.1976.4328548· OSTI ID:7343197

Adams, J R; Coppage, F N

The primary failure mechanism of CMOS devices in an ionizing radiation environment is a threshold voltage shift in both the p-channel and the n-channel devices due to a build up of radiation induced fixed charge in the silicon dioxide and the creation of surface states at the silicon-silicon dioxide interface. It has been observed that many CMOS device types exhibit milliampere range post-rad n-channel leakage for doses between 10/sup 4/ - 10/sup 5/ rad (Si) even though the gate oxide threshold shift is much less than that required for inversion in the channel region. This is caused by field oxide inversion under the gate metal due to improper or a lack of guardbanding of the n-channel device for a radiation environment. The solution to this problem in hardening CMOS devices involves guardbanding the n-channel devices and extending the gate oxide under the gate metallization over the guardband. Experimental results on devices which utilize this technique has shown it to be an effective solution to the problem. Data on several types of CMOS devices are presented to illustrate the n-channel leakage problem and the solution. Special guard-banding problems encountered with silicon gate on bulk silicon devices are also described and possible solutions to these problems are discussed.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: AT(29-1)-789
• OSTI ID: 7343197
• Report Number(s): SAND-76-5410; CONF-760728-4; TRN: 08-019574
• Resource Relation: Journal Volume: 23; Journal Issue: 6; Conference: IEEE annual conference on nuclear and space radiation effects, San Diego, CA, USA, 26 Jul 1976
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
INTEGRATED CIRCUITS
PHYSICAL RADIATION EFFECTS
MOS TRANSISTORS
BUILDUP
FAILURES
LEAKAGE CURRENT
RADIATION HARDENING
CURRENTS
ELECTRIC CURRENTS
ELECTRONIC CIRCUITS
HARDENING
MICROELECTRONIC CIRCUITS
RADIATION EFFECTS
SEMICONDUCTOR DEVICES
TRANSISTORS
440200* - Radiation Effects on Instrument Components
Instruments
or Electronic Systems