Improved Frequency Response in a SiGe npn Device through Improved Dopant Activation

Abstract

We study the impact of improved dopant activation in a BiCMOS SiGe technology, using laser annealing to improve activation, and a low temperature contact module to avoid de-activation. We present the results of simple DC test structure measurements and high frequency bipolar transistor measurements. Improved activation significantly reduces sheet resistance, particularly for polysilicon layers. Likewise, reductions in the bipolar device resistance parasitics cause an improvement in maximum power gain frequency (fMAX).

On the Challenges of SiGe HBTs in Advanced BiCMOS Technology Toward Half THz fMAX

“…Achieving Reduction in Both C CB and R B Advanced doping activation control technique, such as the millisecond anneal techniques (MSA) have been demonstrated to reduce the base resistance while maintaining a relatively thin base (17). Taking advantage of the MSA technique and associated silicide process, a series of experiments has been carried out.…”

SiGe HBTs in 90nm BiCMOS Technology Demonstrating fT/fMAX 285GHz/475GHz through Simultaneous Reduction of Base Resistance and Extrinsic Collector Capacitance

“…This means that C CB can be reduced independently from base resistance reduction, presenting a potential mechanism overcoming the usually inherent R B /C CB trade-offs. Simultaneous Reduction of R B and C CB for 285/475GHz f T /f MAX Advanced doping activation control technique, such as the millisecond anneal techniques (MSA) have been demonstrated to reduce the base resistance while maintaining a relatively thin base (19). Through a series of experiments, an optimum MSA temperature was determined.…”