Title :
High-Current-Gain InP/GaInP/GaAsSb/InP DHBTs With fT = 436 GHz
Author :
Liu, H.G. ; Ostinelli, O. ; Zeng, Y.P. ; Bolognesi, C.R.
Author_Institution :
Swiss Fed. Inst. of Technol. (ETH Zurich), Zurich
Abstract :
Combining a pseudomorphically strained (Ga,In)P emitter with a GaAs0.6Sb0.4 base effectively eliminates the emitter heterojunction type-II conduction band offset in InP/GaAsSb double heterojunction bipolar transistors (DHBTs). A peak fT of 436 GHz at JC = 10 mA/mum2, with BVCEO = 3.8 V, is achieved with 0.6 times 5 mum2 InP/GalnP/GaAsSb DHBTs with a 75-nm InP collector. Compared to a binary InP emitter, the (Ga,In)P emitter doubles the DC current gain from 166 to 338 for otherwise identical devices. These are the highest DC current gain and cutoff frequencies to date in uniform base GaAsSb DHBTs. The gain improvement reported here will greatly facilitate device design tradeoffs that are encountered while scaling InP/GaAsSb DHBTs toward higher frequencies by allowing higher base doping levels and smaller emitter geometries.
Keywords :
III-V semiconductors; conduction bands; gallium arsenide; gallium compounds; heterojunction bipolar transistors; indium compounds; semiconductor doping; DC current gain; InP-GaInP-GaAsSb-InP - Interface; base doping levels; cutoff frequencies; double heterojunction bipolar transistors; emitter geometries; emitter heterojunction type-II conduction band offset; high-current-gain DHBT; pseudomorphically strained emitter; Cutoff frequency; Doping; Double heterojunction bipolar transistors; Epitaxial growth; Epitaxial layers; Focusing; Gallium arsenide; Geometry; Heterojunction bipolar transistors; Indium phosphide; Current gain; GaAsSb; GaInP; InP; cutoff frequency $(f_{T})$ ; double heterojunction bipolar transistors (DHBTs); type II band line up;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.905461
