Inp-based And Phosphorus-containing Heterojunction Bipolar Transistor Materials, Structural Design And The Gas Source Molecular Beam Epitaxial Growth

Heterojunction bipolar transistor (HBT) is one of the most important high speed devices in optical and wireless communication systems. In this dissertation, InP-based and phosphorus-involved HBT structural materials and devices grown by gas source molecular beam epitaxy (GSMBE) were studied theoretically and experimentally. The main results obtained in this work were summarized as follows:1. InGaAs/InP DHBT structure with n-sheet doped emitter and collector was analysed. The results show that the DHBT has many advantages including low offset voltage, good I-V characteristics, and high cutoff frequency. A DHBT current transport model was also developed and used to analyze the influence of the parameters such as n-sheet doping layer thickness and doping concentration on I-V characteristics and current gain.2. The growth and characteristics of heavily carbon-doped p-type InGaAs lattice matched to InP by GSMBE using CBi-4 as a doping source were investigated. The effects of growth temperature, group V supply pressure and CBr4 supply pressure on the composition, hole concentration and mobility of carbon-doped InGaAs epi-layer were studied. The dependence of hydrogen passivation effect on different AsHa supply pressure and different growth temperature were also researched. Ultrahigh hole concentration of 1 X 1020/cm3 with room-temperature mobility of 45cm2/Vs was achieved without any post-growth annealing. The carbon-doped InGaAs layers grown by GSMBE using CBr4 as doping source were used for the growth of InGaAs/InP HBT structures.3. InGaAs/InP and InGaP/GaAs HBT structural materials with Be- and C-doped base layers were grown by means of GSMBE and the properties of the material were studied. The results show that the quality of the materials grown in this work is high enough to be applied to the device fabrication. Large area emitter InGaP/GaAs HBTs were fabricated. The offset voltage and the breakdown voltage are 0.15V and 8V separately. The common emitter current gain as high as 160 was obtained. It means that the HBT structural materials developed in this work can satisfy the high speed HBT circuit applications.