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The overall purpose of this paper (including Part I, in this issue) is the prediction of the ultimate electrical high-frequency performance potential for SiGeC heterojunction bipolar transistors under the constraints of practical applications. This goal is achieved by utilizing most advanced device simulation tools with parameters calibrated to existing experimental results. This Part I outlines the overall scaling procedure and then focuses on the vertically scaled structure. According to isothermal device simulation, the “ultimate” doping profile yields a peak transit frequency fT of almost 1.5 THz, a \BVCEO above 1 V (dependent on BE bias) and a zero-bias internal base sheet resistance of about 3 \k\Omega/\sq. The reasons for achieving a higher product fT \BV \rm CEO ( > \1.5\ \THzV) than anticipated from the classical Johnson limit are explained. Finally, it is found that fT is limited by the minority charge stored in the BE junction and that \BVCEO is mainly determined by the tunneling mechanisms in the base–collector space-charge region. [ABSTRACT FROM PUBLISHER]

The overall purpose of this paper is the prediction of the ultimate electrical high-frequency performance potential for SiGe C HBTs under the constraints of practical applications. This goal is achieved by utilizing advanced device simulation tools with parameters calibrated to experimental results of most advanced existing technologies. In addition, detailed electrostatic and electrothermal simulations are performed for determining the parasitic capacitances, temperature increase, and safe operating area of aggressively scaled devices. The important figures of merit are then determined from circuit simulation employing an accurate compact model incorporating all relevant physical effects. Based on the vertical profile found in Part I, this paper focuses on achieving a balanced device design by lateral scaling. It is shown that the peak values of (fT, f\max) around (1, 1.5) THz may be achievable. Such a performance limit provides still significant headroom for further developing existing processes and makes SiGe C HBTs well-suitable for highly integrated millimeter-wave applications operating within the low-end of the terahertz gap. [ABSTRACT FROM PUBLISHER]

Abstract: Vertical and horizontal scaling is aggressively used to increase frequency performances of SiGe Heterojunction Bipolar Transistors. As a result, the evaluation of the extrinsic electrostatic capacitances becomes increasingly important. In this article, we investigate the electrostatic parasitic capacitance in 230–335GHz SiGe transistor technologies. We compare measured electrostatic capacitances with calculations based on a finite elements modelling. We conclude that the influence of the parasitic capacitances only screens the intrinsic performances of the devices by 10–14% but an accurate estimation of theses parasitics must be included in the design of next generation SiGe HBT. [Copyright &y& Elsevier]