The Effect of Selectively and Fully Ion-Implanted Collector on RF Characteristics of BJT Devices

A selectively ion-implanted collector (SIC) is implemented in a 0.8μm BiCMOS process to improve the RF characteristics of the BJT devices. The SIC BJT device has better f t and f max than the FIC (fully ion-implanted collector) BJT device because the extrinsic base-collector capacitance is reduced by the SIC process. The I t is 7.8 GHz and f max is 9.5 GHz for the SIC BJT device while the f t is 7.2 GHz and f max is 4.5 GHz for the FIC BJT device when biased at V ce =3.6V and J c =0.07 mA/μm 2 . The noise parameters are the same for both BJT devices but the associated gain is higher for the SIC BJT device.