Internship for Research in GaAs Device and Circuit Modeling

9311775元进行砷化镓光电子器件、BiCMOS电路和HBT的理论和实验研究。光电器件研究将研究砷化镓光导体和光电晶体管，开发用于光电电路设计的大信号和小信号异质结光电晶体管和光电二极管模型。MEDICI将用于获得GaAs材料中光子和电子特性的物理洞察，并且将从实验和理论两方面研究不同光照对许多器件参数的影响。BiCMOS的研究主要集中在辐射和尺度对BiCMOS电路性能的影响。BiCOMS测试电路将暴露在伽马和中子辐射下，并对辐照后的性能进行表征。本文将建立一个预测BiCMOS逆变电路“失效模式”开始的模型。在异质结双极晶体管中，研究了基于器件跨导的互调理论。研究了早期电压异质结耗尽电容和异质结扩散电容。本文还对HBT振荡器的相位噪声进行了研究。将研究雪崩击穿、带不连续、负集电极电流和表面复合对相位噪声的耦合效应。此外，电源电压缩放对传呼机和发射机等通信电路性能的影响将被检查。＊＊＊

9311775 Yuan Theoretical and experimental studies GaAs optoelectronic devices BiCMOS circuits and HBT's will be undertaken. The optoelectronic device research will study GaAs photoconductors and phototransistors, developing large-signal and small-signal heterojunction phototransistor and photodiode models for optelectronic circuit design. MEDICI will be used for obtaining physical insight into photon and electron properties in GaAs materials, and the effect of different light illumination on a number of device parameters will be investigated both experimentally and theoretically. The study of BiCMOS research will focus on effects of radiation and scaling on BiCMOS circuit performance. BiCOMS test circuits will be exposed to gamma and neutron radiation and post-irradiation performance will be characterized. A model to predict the onset of the 'failure mode' of a BiCMOS inverter circuit will be developed. In the heterojunction bipolar transistor research the theory of intermodulation based on device transconductance. Early voltage heterojunction depletion capacitance, and heterojunction diffusion capacitance will be studied. The phase noise of the HBT oscillator will also be studied. Coupling effects of avalanche breakdown, band discontinuity, negative collector current, and surface recombination on phase noise will be investigated. Furthermore, the impact of supply voltage scaling on the performance of communication circuits like the pager and the transmitter will be examined. ***