The effect of selectively and fully ion-implanted collector on RF characteristics of BJT devices

Abstract

A selectively ion-implanted collector (SIC) is implemented in a 0.8 mu m 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 f(t) is 7.8GHz 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 =3.6 V and J(c) = 0.07 mA/mu m(2). The noise parameters are the same for both BJT devices but the associated gain is higher for the SIC BJT device.