The influence of the emitter orientation on the DC and low frequency noise characteristics of GaInP/GaAs HBTs

The present paper focuses on the influence of the emitter orientation on the electrical characteristics of GalnP/GaAs HBTs. The investigation was carried out by means of DC and Low Frequency Noise (LFN) measurements in the 250Hz-100kHz frequency range. Samples featuring a conventional Carbon-doped base and an Indium-codoped/Carbon-doped base were available. We demonstrated that the emitter orientation has an impact both on the DC and LFN characteristics of HBTs. This behaviour has been attributed to piezoelectric effects and surface recombinations in the extrinsic base region around the emitter perimeter .