SIMULATION OF THE MECHANICAL-STRESS EFFECT IN BIPOLAR JUNCTION TRANSISTORS

摘要

This paper shows how to simulate the mechanical-stress effect in bipolar junction transistors using well-known circuit simulators. The mechanical stress induced by silicon wafer processing or packaging has a significant influence on the magnitude of the base-emitter voltage of the bipolar transistors. This so-called piezojunction effect is the dominant cause of inaccuracy and long-term instability of many basic analogue building blocks such as bandgap voltage references, temperature sensors and DA-converters. On the other hand, the same effect can be used to design new sensors structures. The development of new stress sensors for low-power and miniaturized systems is desirable and the piezojunction effect meets the requirements. The inclusion of the piezojunction-effect model in circuit simulators improves the reliability of the simulated results and provides to the IC designers the magnitude of the stress-induced parameters change. At the same time, designers of microelectromechanical systems can use this simulation model to evaluate new systems.