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Title: GaAs MMIC: recovery from upset by x-ray pulse

Abstract

Tolerance for fast neutrons and total ionizing dose is a feature of GaAs microwave monolithic integrated circuits (MMIC). However, upset during an ionizing pulse is expected to occur and delayed recovery due to backgating may be a problem. The purpose of this study of an experimental MMIC design is to observe the recovery of oscillator power output following upset by a short ionizing pulse as a function of applied bias, dose per pulse and case temperature.

Authors:
;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (USA)
OSTI Identifier:
5236391
Report Number(s):
SAND-86-0697C; CONF-861164-1
ON: DE86014109
DOE Contract Number:
AC04-76DP00789
Resource Type:
Conference
Resource Relation:
Conference: Government microcircuit application conference, San Diego, CA, USA, 11 Nov 1986; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; INTEGRATED CIRCUITS; PHYSICAL RADIATION EFFECTS; ELECTRONIC CIRCUITS; FAST NEUTRONS; IONIZING RADIATIONS; X RADIATION; BARYONS; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; FERMIONS; HADRONS; MICROELECTRONIC CIRCUITS; NEUTRONS; NUCLEONS; RADIATION EFFECTS; RADIATIONS; 440200* - Radiation Effects on Instrument Components, Instruments, or Electronic Systems

Citation Formats

Armendariz, M.G., and Castle, J.G. Jr. GaAs MMIC: recovery from upset by x-ray pulse. United States: N. p., 1986. Web.
Armendariz, M.G., & Castle, J.G. Jr. GaAs MMIC: recovery from upset by x-ray pulse. United States.
Armendariz, M.G., and Castle, J.G. Jr. 1986. "GaAs MMIC: recovery from upset by x-ray pulse". United States. doi:.
@article{osti_5236391,
title = {GaAs MMIC: recovery from upset by x-ray pulse},
author = {Armendariz, M.G. and Castle, J.G. Jr.},
abstractNote = {Tolerance for fast neutrons and total ionizing dose is a feature of GaAs microwave monolithic integrated circuits (MMIC). However, upset during an ionizing pulse is expected to occur and delayed recovery due to backgating may be a problem. The purpose of this study of an experimental MMIC design is to observe the recovery of oscillator power output following upset by a short ionizing pulse as a function of applied bias, dose per pulse and case temperature.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1986,
month = 1
}

Conference:
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  • The temperature dependence of pulsed neutron and flash x-ray radiation effects was studied in GaAs MMICs. Above room temperature the long term current transients are dominated by electron trapping in previously existing defects. At low temperature in the range 126 to 259 K neutron induced lattice damage appears to play an increasingly important role in producing long term current transients.
  • The authors have developed a low-cost, manufacturable, 2-layer coating process for on-wafer encapsulation of GaAs MMICs. This packaging approach takes advantage of the low dielectric permittivity of polymers such as Benzocyclobutene (BCB) and the sealing properties of ceramics such as SiC to provide both mechanical protection to MMICs during handling and also hermetic-like equivalence to moisture with predictable changes in the electrical performance of the coated MMICs. The effects of coatings on FET parameters, spiral inductors and a two stage X-Band LNA have been investigated. Results on FETs indicate that the internode capacitances Cgs and Cgd exhibited the same incrementalmore » change of 0.035 pF/mm (3 and 25 % increase respectively), while Cds changed by 0.051 pF/mm (27% increase) with very minimal changes in the other FET parameters. The only observed change in spiral inductors was a 112% increase in Cp from 0.006 pF to 0.013 pF. The LNA exhibited a 1 GHz shift in frequency response from 7 to 11 GHz to 6 to 11 GHz with no substantial changes in gain and noise figure. Preliminary reliability investigations on coated devices did not show any failures after 150 hours in autoclave (120C, 100% humidity).« less
  • In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10% to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The finalmore » measurements were performed were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1. This linescan is an average of 5 linescans in the immediate vicinity to reduce noise levels. A SEM image of the area is shown in Figure 2. To obtain a rough estimate of the slopes of the gate lines at the edges, the sample was tilted to 75 degrees and the image in Figure 3 was obtained. From this figure a rough estimate of the sloped edges, using a protractor, was obtained, approximately 27 degrees, +/-5 degrees.« less
  • Microwave parameters drifted significantly for two out of twenty- nine GaAs MESFET-based MMICs during ten weeks of storage at 125[degrees]C and 150[degrees]C. Analysis using measured, post- storage, FET characteristics and the microwave behavior indicates that all of the FETs in the MMICs drifted, most likely due to contamination.
  • Microwave parameters drifted significantly for two out of twenty- nine GaAs MESFET-based MMICs during ten weeks of storage at 125{degrees}C and 150{degrees}C. Analysis using measured, post- storage, FET characteristics and the microwave behavior indicates that all of the FETs in the MMICs drifted, most likely due to contamination.