Modelling of SiGe heterobipolar transistors: 200 GHz frequencies with symmetrical delay times

High speeds in a single chip

“…When de-embedded S-parameter measurements are made, it is not this ideal inner transistor but a transistor with series resistances to the three contacts (emitter, base, collector) that is measured [18]. The maximum oscillation frequency f max of the HBT is given by…”

Silicon Based Heterostructures: Advances in Channel Materials

“…Proven advantages of SiGe heterodevices Integrated npn HBT transistors are now commercially available with around 200 GHz transit frequency ft [25,26] and maximum oscillation frequency fmax, the research is targeting towards the Terahertz realm (half THz is demonstrated) with npn transistors and above 100 GHz for pnp transistors. This strained SiGe layer transistor proved the processing possibilities and reliability of SiGe / Si heterostructures.…”

Efficient Approach to Optimization of f/sub γ for Graded-Base SiGe HBTs

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Most studies of f T for SiGe HBTs have been focused on one or 2 components of the total delay time, τ EC [1][2][3][4]. The present work takes into account all crutial components of the total delay time τ EC to optimize f T , including the transit times across the quasi-neutral regions (τ E and τ B ) and the depletion layer (τ BC ) and the charging times (τ JEB and τ JBC ) due to the junction capacitances (C EB and C BC ).

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“…To minimize τ B , a graded base has been widely used [3][4][5]. Also, a large bandgap reduction at the EB junction can minimize τ E and τ JEB , [2,6,7]. A trapezoidal Ge profile in Fig.…”