Base-region optimization of SiGe HBTs for high-frequency microwave power amplification

Abstract

Abstract-The base-region optimization of SiGe power heterojunction bipolar transistors (HBTs) for high-frequency microwave power amplification is investigated. It is found that employing a heavily doped base region in conjunction with a high Ge content of proper profile can effectively improve the large-signal power-gain values of SiGe HBTs while maintaining their high breakdown voltages and thus allow them to be efficiently operated with high power at higher microwave frequencies. More importantly, with such a base-region optimization, not only lateral-scaling requirements can be relaxed but also a common-base configuration for power amplification using these devices can be favored, which further enhances the power-gain values of SiGe power HBTs at high frequencies. Load-pull experimental results are presented to show the highest figure-of-merit power performance of SiGe power HBTs with an optimized base region. The power performance of SiGe power HBTs operated at X -band with different base-region designs was also compared to illustrate the significant benefits that result from the base-region optimization.Index Terms-Common base (CB), doping profile, figureof-merit (FOM), load pull, microwave, power amplification, power gain, SiGe heterojunction bipolar transistors (HBTs).

On the scaling of emitter stripes of SiGe power HBTs

“…Moreover, as shown in figure 8, increasing N B can effectively improve f max of large-area power SiGe HBTs. For this reason, using a higher base doping concentration than emitter doping concentration in SiGe HBTs has resulted previous SiGe power HBTs with record power performance results [3].…”

Characteristic Influence of DC Bias on SiGe HBT Linearity and Power Gain under Different Operation Configurations

“…Due to high power gain values available from these devices, both common-emitter (CE) and common-base (CB) configurations have been used for power amplification. In particular, as the poweramplification frequencies move to higher frequency bands, the CB configuration has shown its particular superiority (e.g., higher power gain and higher power-added efficiency) in comparison to the CE configuration, as evidenced in the recent reports (2)(3)(4)(5)(6). Considering the fact that linearity is also of a great concern in linear amplifiers, we recently have investigated the linearity characteristics of the CB configuration and analytically compared the linearity characteristics between the CE and the CB configurations under equivalent bias conditions (i.e., the same base-emitter (V BE ) and the same base-collector junction voltages (V CB ) for the CE and the CB configurations) without involving impedance matching at the input/output of the devices (7).…”

Compositional analysis of Si nanostructures: SIMS–3D tomographic atom probe comparison

“…As SiGe finds broader use in nano-devices, greater attention has been focused on understanding the capabilities and limitations of techniques for compositional analysis [1][2][3]. As feature length scales in these devices shrink below 10 nm, variations in the chemical composition of these devices-specifically the location of dopant atoms and the quality of interfaces between regions-may have a significant impact on the final electrical characteristics of the device.…”