Ka-band InP high electron mobility transistor monolithic microwave integrated circuit reliability

The reliability of AlInAs/GaInAs high electron mobility transistor (HEMT) m onolithic microwave integrated circuits on InP substrates from HRL Labs has been studied with elevated-temperature lifetests on Ka-band LNAs, as well as ramped-voltage tests on individual capacitors. In the lifetests the LNAs were put under normal DC bias, and aging was accelerated by heating to cha nnel temperatures of 190 degreesC and 210 degreesC. Room-temperature charac terizations involved DC tests of HEMT parameters as well as 30 GHz measurem ents of gain, noise figure and phase, Aging caused the noise figure to drop by a few tenths of a dB, and the phase changed by +/- 10 degrees. The gain dropped gradually by several dB. Taking I dB drop in gain as the failure c riterion, we find an activation energy of 1.1 eV, and a mean time to failur e (MTTF) at an operating channel temperature of 70 degreesC of 7 x 10(6) h. In the ramped-voltage tests, 10 x 10 mum(2) capacitors were taken to break down at two different temperatures, and several ramp rates. This yielded a voltage acceleration factor of gamma = 36-39 nm/V, and thermal activation e nergy of 0.11-0.13 eV. Next, ramped voltage tests were conducted on 200 x 2 00 mum(2) capacitors, typical of those in circuits. These were done at 25 d egreesC and 3.0 V/s only, and at least 1000 specimens were tested per wafer . The known acceleration factors were used to find the MTTFs at 70 degreesC , with operating biases of 5 or 10 V. For the majority of the population th e MTTFs are about 10(9) h, while only 0.07% of the population has MTTF less than 1 x 10(6) h. The combination of results from elevated-temperature lif etests and ramped-voltage capacitor tests indicates excellent reliability f or this MMIC technology in terms of known "wearout" failure mechanisms. (C) 2001 Elsevier Science Ltd. All rights reserved.