The effects of the conditions of the collector formation on electrical characteristics of the packaged SiGe hetero-junction bipolar transistors (HBT) were investigated. While the DC characteristics of SiGe HBTs such as IV characteristic, forward current gain, Early voltage, and breakdown voltage were hardly changed after packaging, the AC characteristics such as f τ andf max were degraded severely. With the rise of the collector concentration, the break-down voltage decreased but the f τ increased. Additionally, β and f τ values were kept high in the range of elevated collector current due to the increase of the critical current density for the onset of the Kirk effect. The devices As implanted before the collector deposition showed lower breakdown voltage and higher f τ than the others, which seems to be originated from the As up-diffusion resulting in the thinner collector.