low noise gallium arsenide fet reliability data description the following cumulative test re- sults have been obtained from testing performed at agilent tech- nologies in accordance with the latest revision of mil-std-883. data was gathered from the prod- uct qualification, reliability monitor, and engineering evalua- tion for the lyg gaas process. for the purpose of this reliability data sheet, a failure is any part which fails to meet the electrical and/or mechanical specification listed in the product data sheet. atf-10xxx ATF-13XXX b. failure rate prediction the failure rate will depend on the junction temperature of the device. the estimated life at different temperatures is calculated, using the arrhenius plot with activation energy of 1.2 ev, and the device thermal resistance of the stress board is 130 c/w, and is listed in the following table. point (1) 90% confidence level (2) junction temp. mttf* mttf mttf t j ( c) (hours) fit (3) (hours) fit (3) 175 3 x 10 -6 333 0.5 x 10 -6 2000 150 2 x 10 -7 50 9.5 x 10 -8 105 100 2 x 10 -9 0.05 9.5 x 10 -8 1.05 47 8 x 10 -11 0.001 3.5 x 10 -11 0.0003 *mttf data calculated from high temperature operating life tests. 1. life test a. demonstrated performance units total total failure rate test name test conditions tested device hrs. failed (%/1k hours) high temperature nominal bias at 150 150,000 0 0 operating life (o.l.) t ch = 175 c, 1000 hrs. high temperature ambient temperature 225 225,000 0 0 storage (hts)* t a = 150 c, 1000 hrs.
c. example of failure rate calculation at 100 c with a device operating 8 hours a day, 5 days a week, the percent utilization is: % utilization = (8 hours/day) x (5 days/week) / (168 hours/week) = 25% then the point failure rate per year is: (5 x 10 -10 ) x (25%) x (8760 hours/year) = 1.1 x 10 -6 % per year likewise, the 90% confidence level failure rate per year is: (1 x 10 -9 ) x (25%) x (8760 hours/year) = 2.2 x 10 -6 % per year notes: 1. the point mttf is simply the total device hours divided by the number of failures. 2. this mttf and failure rate repre- sent the performance level for which there is a 90% probability of the device doing better than the stated value. the confidence level is based on the statistics of failure distribution. the assumed distribu- tion is exponential. this particular distribution is commonly used in describing useful life failures. 3. fit is defined as failure in time, or specifically, failures per billion hours. the relationship between mttf and fit is as follows: fit = 10 9 /(mttf). 3. flammability test (mil-std-202, method 111): meets needle flame test per ul category d (flaming time <3 sec.) under material classification 94vo. 4. dod-hdbk-1686 esd classification: class i test name mil-std-883 test conditions units tested units failed reference thermal shock 1011 -65 c to +150 c, 100 cycles 368 0 temperature 1010 -65 c to +150 c, 100 cycles 368 0 cycle moisture C +121 c; 100% rh, 96 hrs. 290 0 resistance *mechanical 2002 1500 gs, 0.5 msec. pulse 135 0 shock *acceleration 2001 20,00 gs, one minute all axis 135 0 solderability 2003 245 c, 5 sec. dwell; 245 0 2. environmental tests (*applicable to ceramic packages only) 400 350 300 250 200 150 100 50 25 t j ?junction temperature ( c) 10 4 10 5 10 6 10 7 10 9 10 10 mttf ?mean time to failure (hrs.) 4.0 3.0 2.0 1.5 1.0 0.9 0.8 0.7 0.6 0.5 activation energy (ev) 10 8 1.2 ev www.semiconductor.agilent.com data subject to change. copyright ? 1999 agilent technologies, inc. 5966-2942e (11/99)
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