High performances of InP/InGaAs heterojunction bipolar transistors with a  -doped sheet between two spacer layers

Abstract

New InP/InGaAs δ-doped heterojunction bipolar transistors have been successfully fabricated and demonstrated. The use of a δ-doped sheet between two undoped spacer layers more effectively eliminates the potential spike at the base-emitter junction and lowers the collector-emitter offset voltage. The maximum current gain and offset voltage of 455 (533) and 55 mV (33 mV) are observed, respectively, for the unpassivated (passivated) emitter device at room temperature. The base surface recombination current of the studied devices is also investigated in this paper. The studied devices are therefore promising for practical circuit applications.

Influence of Emitter-Edge-Thinning Thickness on the Heterojunction Bipolar Transistor Performance

“…It is well known that the high electron mobilities and velocities in III-V compound semiconductor materials make GaAs-or InPbased heterojunction bipolar transistor ͑HBT͒ and switch devices attractive for high-speed integrated circuit ͑IC͒ applications. [1][2][3][4] However, for a typical GaAs-based HBT, a lateral diffusion of injected carriers at the exposed base surface between the emitter mesa sidewall and the base ohmic contact leads to the considerable recombinations between electrons and holes. [5][6][7][8][9] In addition, a capture of electrons and holes by surface traps results in an emitter size dependence on the current gain.…”