Abstract
We use the photo-reflectance (PR) technique to measurementsInGaP/InGaAsN/GaAs heterojunction bipolar transistor (HBT)wafer, we fine the change of photo-reflectance spectrum whenthere is a high concentration δ-doping layer added in our sample,and we can obtained electric field、energy gap in thecollector/base、emitter/base by Franz-Keldysh oscillations (FKOs) from photo-reflectance spectrum . In this experiment, the waferwith δ-doping layer will be have a special PR spectrum and theelectric field are more higher then others . This kind of sample cannot become a good-condition device and their current gain equal 1 .To analysis this special phenomenal, we etching our sample anduse photo-reflectance technique . After analysis every layer ofsample, we provide that the special phenomenal when the waferhasδ-doping layer . In this thesis, we guess it was form by the diffusion between epitaxial layer .