The Effects of Compositionally Graded Bases and Annealing on InGaP-GaAs HBTs Grown by MBE using a GaP Decomposition Source

摘要

InGaP-GaAs Single Heterojunction Bipolar Tran-sistors (SHBTs) with a compositionally graded base have been successfully grown by Solid-Source Molecular Beam Epitaxy (SSMBE) using a GaP decomposition source. The device char-acteristics of InGaP-GaAs HBTs with InX Ga1 −X As graded base x :0卣慲潮 →0.1 (MBE 1462) and x :0卣慲潮 →0.05 (MBE 1463) have been compared with conventional HBTs (MBE 1461) to investigate the optimum-grading profile. Additionally the effects of Rapid Thermal Processing (RTP) on Beryllium (Be)-doped InX Ga1 −X As graded base layer lattice matched to GaAs have been investigated at different annealing temperatures. The average current gains of MBE 1461, MBE 1462, and MBE 1463 are 174, 342 and 321, respectively prior to annealing. It was founded that all the devices had no significant degrading Be out-diffusion in the base region up to annealing temperatures of 450 o C .To thebestofourknowledge, these average currents are the highest value ever reported in InGaP-GaAs HBTs with a compositionally grad ase and establish a new benchmark for high gain InGaP-GaAs HBTs.ud