Theoretical Research On InP-Based HBT And The Application Of Monolithic OEIC Of Photoreceiver's Front End

The research work described in this paper were supported by the grants from many research projects, including Doctoral Subjects Research Grants of Ministry of Education, "Monolithic OEIC photoreceiver modules based on RCE photodetectors and HBT" (20020013010) and National Basic Research Program of China, "Basic Research on Integrated Optoelectronic Devices and Microstructure Optical Fibers with Structure and Technology Innovations for Future Advanced Optical Communications" (2003CB314900).As the development of width-band communication system and high capacity of network system, the need of high speed and low power lose device became more and more urgent. For the demand of high performance device and electric circuit, the research of HBT developed rapidly. At present, scientific research often chooses InGaAs whose lattice matches InP. At the same time, because InP/InGaAs HBT has good characteristics, such as it can carry out high doping. This HBT has abrupt heterojuction junction, it has electron transfer rate and low turn on voltage, so it can make high speed and low power lose become true.This paper studied design and fabrication of InP-based HBT based on the theory of the HBT. Research results, as listed below, have been achieved.Because the emitter crowding is one of the factors to limit its capability of loaded current. This paper made a discussion of this topic. The problem of the effect of emitter crowding on base-emitter junction voltage was calculated. Then the relationship between W_eff/W_E(the ratio of effective emitter width and the emitter width) and its influencing factors (e.g. base doping, emitter length, base thickness, emitter width)was studied, so that the structure design of InP based HBT can be optimized.The influence of InP-based HBT's high-frequency characteristic from HBT's structural parameters and it's doping of different layers were studied. The research of doping, width, length, thickness of different HBT's layer(e.g. base layer, emitter layer and collector layer) was achieved. The effect of these factors on charging time, cutoff frequency and maximum oscillation frequency was calculated. Actual situation and the result of calculations optimize the design of HBT were combined.Further study of a novel HBT structure was carried out theoretically, a method to solve the problem that small change on doping of HBT would make dramatic change of energy band was found.At the same time, this structure would had better breakdown voltage characteristic and keep its PIN absorbing layer.The author participated in the fabrication of InP-based HBT. The testing results of this device described as following: as to the 2^μm size style of InP-based HBT, the parameter of f_T was 20GHz.