Accelerated Reliability Testing Research Articles

Burn-In of Incandescent Sign Lamps

This paper describes an experiment in which it was determined that properly designed burn-in can not only eliminate a weak subpopulation, but also stabilize the healthy one. Accelerated life tests have been carried out on 30W sign lamps to show that the time-to-failure pattern is bimodal. The accelerated life data have been used to design burn-in process parameters, and to determine the deterioration caused in the healthy subpopulation by the chosen burn-in. The results showed no decrease in mean life of the healthy lamps. Rather, increased stability (lower standard deviation in life) has been observed. The burn-in procedure with parameters 240V and duration in the range 15-20s was successfully applied to the 30W sign lamps in order to eliminate the weak subpopulation. Due to fast turnaround of the procedure it can be implemented at the end of the production line. The high temperature thermal treatment of filaments during burn-in seems to relax structural stresses caused by fabrication process. The fact that the power coefficient obtained here differs from the one quoted by GE Technical Information TP-110 as well as by IES Lighting Handbook (Reference Volume 1984) should alert users of accelerated reliability tests to be wary of uncritical application of experimental factors taken from the literature, including this paper.

Comparisons of instabilities in scaled CMOS devices between plastic and hermetically encapsulated devices

Scaling down of transistor cell sizes causes some instabilities in CMOS devices under high temperature or high humidity bias stress, especially in plastic encapsulated devices. On CMOS test transistors with various kinds of the passivation layer, accelerated reliability tests have been conducted in this study. As a result of tests, it has been found that devices with a phosphosilicate glass passivation layer show remarkable threshold voltage shifts, which depend on the gate length, compared with devices with a silicon-nitride passivation layer, in both plastic and ceramic encapsulated devices. This paper describes characteristics of the shift, passivation, and packaging effects on the shift and modeling of the shift mechanism.

InGaAsP LEDs for 1.3-μm Optical Transmission

High-radiance InGaAsP double heterostructure light-emitting diodes (LEDs) that are fast and reliable have been developed for 1.3-μm optical transmission applications. These devices are prepared by liquid phase epitaxy on InP substrates. Improved growth procedures result in large-area wafers (up to 5.4 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) with excellent uniformity and high device yields. Optical power of ∼120 μW can be launched into 0.29-NA, 62.5-μm core fiber. On the basis of accelerated reliability tests the median life of these InGaAsP LEDs is expected to exceed 4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> h at 70° C and current densities up to 40 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The projected failure rate owing to output power degradation (−1 dB) is below 1 FIT. These devices are expected to be useful in lightwave systems operating at data rates ≲140 Mb/s.

Long-Lived (GaAl)As DH Lasers Bonded with In Produced by Eliminating Deterioration of In Solder

Long-lived (GaAl)As DH lasers bonded with In solder have been produced using Mo as a barrier metal. The amount of Au on the Mo was reduced to much less than the amount of In solder to eliminate the deterioration of the latter. The intermetallic formation between In and Au was investigated using a simulation method. An accelerated reliability test at 50 and 70°C, gave the activation energy of degradation as 0.52 eV. The mean time required for a 50 mA driving current increase in these long-lived devices was estimated to be 1.9×106 hours at 25°C in operation at 5 mW/facet.

On accelerated reliability tests of silicon transistors : K. Tomášek. Nachrichtentech. Zeits.24, No. 1 (1971), p. 43. (In German.)

On accelerated reliability tests of silicon transistors : K. Tomášek. Nachrichtentech. Zeits.24, No. 1 (1971), p. 43. (In German.)

Method of substantiating forced regimes for accelerated reliability tests of medical gas apparatus

Method of substantiating forced regimes for accelerated reliability tests of medical gas apparatus