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Abstract: We report on a simple Inductively Coupled Plasma-Reactive Ion Etching (ICP-RIE) process with Cl2/N2 chemistry to process InP based, self-aligned HBTs with sub-micron emitters. Since the layer to be etched is in the range of 150nm (the thickness of emitter cap and emitter layers), a low etch rate is beneficial. On the other hand, it is also necessary to use chemistries without hydrogen to prevent any possible hydrogen passivation. Therefore, in this work, Cl2/N2 chemistry is selected and a plasma process providing an etch rate of 120nm/min is optimized. Not only the etch rate but also the electrical and the surface quality of the wafers are examined. It has been illustrated that the etch rate of the optimized process is uniform over the wafer and it is reproducible. In addition to that, it has been shown with electrical measurements that there is no degradation in the material quality. To test the optimized process, sub-micron HBTs are fabricated and the RF measurements have shown an f max of 340GHz which make them to be used in high speed communication systems. In addition to that, lower and controlled under etch gives better current gain distribution over the wafer leading better device models and resulting in better yield in MMICs. [Copyright &y& Elsevier]

Abstract: This work examines the utility of semi-physical vertical bipolar inter-company (VBIC) model for the first time to develop for an accurate, easy and fast scaling methodology for high-frequency SiGe:C heterojunction bipolar transistors (HBTs) with a peak f T of 75GHz fabricated in a low-cost BiCMOS technology. The methodology allows one to find transistor models from single-finger transistor to multi-finger and variable length emitter devices with a minimal parameter extraction procedure. The devices modeled include several base–emitter structures in parallel, on top of a single collector to obtain different transistor area. The scaling rules are given in detail. Using this methodology, scalable VBIC model parameters were generated to describe the DC and RF behavior of SiGe:C HBTs up to peak f T and f max within ±10% accuracy. The key advantage of this methodology is that one does not need any special test structure while keeping the extraction procedure simple and fast. [Copyright &y& Elsevier]