ABSTRACT
The operating characteristics of Heterostructure Bipolar Transistors (HBTs): have been shown to suffer degradation under temperature and current stress, leading to concerns about device reliability. Theoretical and experimental studies of Recombination-Enhanced -Impurity-Diffusion (REID) in AlGaAs/GaAs HBTs were performed in order to determine the cause of the degradation. The theoretical investigation was carried out using a one-dimensional solution of the Schrödinger, Poisson and current continuity equations, including an exact calculation of tunnelling and thermionic field emission at the heterojunctions. Temperature stressing of biased devices was performed at junction temperatures of 200, 215 and 230 C. The results support REID as the cause of the degradation in the AlGaAs/GaAs devices and the activation energy and REID coefficient are calculated.
