Epitaxial Growth Of Gaas-based Hbt Material And Its Characteristics

In this thesis, heterojunction bipolar transistors (HBTs) and materialswere studied theoretically and experimentally from the viewpoint of thestructural design and growth technology In addition, based on the theorycalculation and simulation, the selection of the microstructure of the Ⅲ-V compound semiconductor applied in HBT devices was studied in detail Thefabrication processing and devices properties of samples prepared by GSMBEwere investigated The results presented in this thesis can be sununarized asfollowingWe calculate the distribution of the carriers in HBTs based on Fermistatistic function And the distributlon of the carriers is compared with theresult of calculations based on Boltzmann statistic function Meanwhile, onthe basis of thermionic field-diffusion model, we study the numericalinvestigation of the current performance of HBTs The influences of dopantconcentration of emitter and base and the thickness of space layer werediscussed Particularly, we discussed and calculated the dc properties andeach current of the structure of δ-doped AlGaAs/GaAs and InGaP/GaAs materialsAn improved double δ-doped structure by growing both of the space layers wassuggestedUsing AsH₃, PH₃ as gas sources and Al,Ga,In as solid sources, GaAs. AlGaAsand InGaP thin films were investigated by GSMBE High quality materials suchas GaAs,AlGaAs/GaAs,InGaP/GaAs were obtained by optimizing the growthcondition The resu1ts 1ndlcated that these studies would be a good foundationfor further device fabrication0n the basis of InGaP/GaAs mater1als fabricated by GSMBE, large sizeddevices with good electrical current properties were obtained Themeasurement resu1ts indicated that the current gain was up to 320...