ABSTRACT
A b s tra c t. Wideband HBTs are obtained by thinning the base and collector, increasing current density, decreasing emitter contact resistivity, and reduc ing the emitter and collector junction widths. In digital ICs, increased emit ter current density and reduced emitter resistivity are critical requirements. We have fabricated submicron HBTs using substrate transfer processes, and have obtained devices with extremely high mm-wave gains. Amplifiers with 6.3 dB gain at 175 GHz have been fabricated, and 75 GHz true static fre quency dividers demonstrated.