Characterization of bias-stressed carbon-doped GaAs/AlGaAs power heterojunction bipolar transistors

Thermal characteristics of InGaP/GaAs HBT ballasted with extended ledge

“…The JA has been separated from the total leakage current by combining different geometry diodes, as described in [7]. The J A normally consists of the J dA , and the J gA [1].…”

“…A cobalt silicide with titanium capping layer was applied. Junctions with different geometry have been studied in order to separate the current and capacitance components using the procedure reported elsewhere [7].…”

“…The thermal instability can be reduced by use of a ballast resistor in series with each emitter or base [2], [3] or by thermal shunt techniques [4]. On the other hand, it is well known that a passivation ledge around an emitter periphery must be incorporated to ensure the reliability [5]- [7]. Thus, the spacing between an emitter mesa and a base electrode is always introduced to some extent.…”

Model for degradation of GaAs/AlGaAs HBTs under temperature and current stress

“…These crystalline defects are generated as a result of non-radiative electron-hole recombination events [5,6]. Substantial evidence, including TEM[31 and electrical measurements [4] supports defect formation as leading to degradation in HBTs as well. As in LEDsLDs, this defect formation is probably recombination-enhanced.…”

“…Because of the similarities between HBTs and LEDsLDs, several authors have suggested that HBT degradation is analogous to LED/LD degradation [3,4]. In LEDs/LDs, light output intensity decreases after bias stress due to an increase in non-radiative recombination centers associated with crystalline defects.…”