Title :
Heterojunction bipolar transistors with emitter barrier lowered by /spl delta/-doping
Author :
Chen, H.R. ; Huang, C.H. ; Chang, C.Y. ; Lee, C.P. ; Tsai, K.L. ; Tsang, J.S.
Author_Institution :
Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
An npn heterojunction bipolar transistor with a Si-/spl delta/-doped layer at the emitter-base hetero-interface is demonstrated. The Si /spl delta/-doped layer reduces the potential spike at the emitter junction. This design reserves the abruptness of the heterojunction, reduces electron barrier and increases the hole barrier simultaneously. Experimental results show that the HBT´s turn-on characteristics are greatly improved while the current gain remains high. The offset voltages as low as 44 mV have been obtained. Very high current gains at very low collector current densities are obtained.<>
Keywords :
III-V semiconductors; aluminium compounds; current density; gallium arsenide; heterojunction bipolar transistors; p-n heterojunctions; /spl delta/-doping; 44 mV; GaAs-AlGaAs-GaAs; Si; Si /spl delta/-doped layer; Si-/spl delta/-doped layer; current gain; electron barrier; emitter barrier; emitter junction; emitter-base hetero-interface; heterojunction bipolar transistors; high current gain; hole barrier; npn heterojunction bipolar transistor; offset voltages; potential spike; turn-on characteristics; very low collector current densities; Bipolar transistors; Charge carrier processes; Current density; Doping; Double heterojunction bipolar transistors; Heterojunction bipolar transistors; Low voltage; Molecular beam epitaxial growth; Narrowband; Substrates;
Journal_Title :
Electron Device Letters, IEEE
