The Research of Temperature characteristics of SiGe HBT and the Reliability under Thermal Stress

The temperature characteristics of SiGe HBT and its reliability under thermal stress are studied. The experiment results indicate that the current gain at 77K is much larger than the one at 290K. And there is a critical value of I C , which is 2×10−4A. Over this value, the gain increases with the decrease of the temperature. But below the value, the gain drops with the decrease of the temperature. The current ideal factor is smaller than 2 when the temperature is over 193K, but larger than 2 at 193K or below. Besides this, the thermal stress experiments for the base-emitter junction were taken under 100°C and 150°C, and the stress time was 90 hours and 30 hours, respectively. The experiment results indicate that the device characteristic parameters fluctuate under the different thermal stress conditions. The annealing and degeneration play the collective role in the characteristics fluctuating under the thermal stress condition.