Open AccessInvestigation of the impact of band offset perturbations on the performance of abrupt HBT with heavily doped base
Author(s) -
Shouli Zhou,
Huang Hui,
Huang Yong-qing,
Xiaomin Ren
Publication year - 2007
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.56.2890
Subject(s) - thermionic emission , quantum tunnelling , materials science , doping , common emitter , dopant , heterojunction bipolar transistor , band offset , condensed matter physics , impurity , diffusion , optoelectronics , offset (computer science) , band gap , transistor , bipolar junction transistor , valence band , physics , voltage , thermodynamics , electron , quantum mechanics , computer science , programming language
Heavy impurity doping leads to bandgap narrowing (BGN) and this causes perturbations to the value of the band offsets at the hetero-interface. As a result, the form and height of energy barriers in abrupt HBT is disturbed, which changes the value of the current flowing through its interfaces. The analysis is based on the thermionic field-diffusion model which combines the drift-diffusion transport in the bulk of the transistor with the thermionic emission and tunneling at the base-emitter interface. The calculations reveal a more important role to the transport of carriers played by the modification of the built-in potential than that of the range of barrier energies available for tunneling because the impact of the built-in potential on the current is exponential. Therefore, it is important for a better description of the currents to use an accurate dopant-dependent BGN distribution model between bands.