Deep submicron InP DHBT technology with electroplated emitter and base contacts

We report the development of a wide bandwidth InP double heterojunction bipolar transistor technology that utilizes novel electroplating processes to form the emitter and base contacts. The technology enables the fabrication of HBTs with deep submicron emitter-base junction dimensions and self-aligned base ohmic contacts. Using this technology, HBTs have been fabricated with emitter junction widths scaled to 0.25 μm. These devices demonstrated peak f_τ and f_max, values of over 300 GHz. The transistors also support high current density operation (J_E>7 mA/μm²) and have a low collector-base capacitance to collector current ratio (C_cb/I_c∼0.55 ps/V), an important parameter for digital logic speed.