Optimisation of buffer layers for InP-metamorphic heterojunction bipolar transistor on GaAs

InP-like metamorphic buffers on GaAs for double heterojunction bipolar transistor (mDHBT) have been grown by molecular beam epitaxy. A two-stage procedure dedicated to DHBT is proposed to study the effect of the metamorphic growth. First, a DHBT-like InP/InGaAs/InP structure is used to evaluate bulk materials quality by photoluminescence, relaxation state by double axis high-resolution X-ray diffraction and surface/interface morphology by optical and atomic force microscopy. Secondly, the emitter-base junction has been studied on metamorphic diodes. First results obtained on In/sub x/Al/sub 1-x/As and ln/sub x/(Al/sub y/Ga/sub 1-y/)/sub 1-x/As gradual buffers, as well as on In/sub 0.52/Al/sub 0.48/As and InP uniform buffers, are presented and discussed.