Small-sized collector-up Ge/GaAs heterojunction bipolar transistors with high gain, low base resistance, and high f/sub max/

1994 ◽  
Vol 15 (2) ◽  
pp. 54-56 ◽  
Author(s):  
M. Kawanaka ◽  
N. Iguchi ◽  
A. Furukawa ◽  
J. Sone
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Gain ◽  
Bipolar Transistors ◽  
Base Resistance

High gain InP/InGaAs heterojunction bipolar transistors grown by OMCVD

1988 ◽  
Vol 93 (1-4) ◽  
pp. 919-923 ◽  
Author(s):  
R. Bhat ◽  
J.R. Hayes ◽  
H. Schumacher ◽  
M.A. Koza ◽  
D.M. Hwang ◽  
...  
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Gain ◽  
Bipolar Transistors

High-Gain Low Turn-On Voltage AlGaAs/GaAsNSb/GaAs Heterojunction Bipolar Transistors Grown by Molecular Beam Epitaxy

2007 ◽  
Vol 28 (12) ◽  
pp. 1083-1085 ◽  
Author(s):  
K. L. Lew ◽  
S. F. Yoon ◽  
H. Wang ◽  
S. Wicaksono ◽  
J. A. Gupta ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Heterojunction Bipolar Transistors ◽  
Molecular Beam ◽  
High Gain ◽  
Bipolar Transistors ◽  
Turn On

Spontaneous and Piezoelectric Polarization Effects on the Frequency Response of Wurtzite Aluminium Gallium Nitride / Silicon Carbide Heterojunction Bipolar Transistors

2008 ◽  
Vol 1069 ◽  
Author(s):  
Choudhury Praharaj
Keyword(s):  
Silicon Carbide ◽  
Frequency Response ◽  
Heterojunction Bipolar Transistors ◽  
Wide Band ◽  
Bipolar Transistors ◽  
Flat Band ◽  
Aluminium Gallium Nitride ◽  
Wide Band Gap ◽  
Base Resistance ◽  
Wide Band Gap Semiconductors

ABSTRACTWe present theoretical calculations for the effect of spontaneous and piezoelectric polarization on the base resistance and frequency response of wurtzite Aluminium Gallium Nitride / Silicon Carbide Heterojunction Bipolar Transistors. Heterojunction Bipolar Transistors ( HBTs ) built using wide band gap semiconductors with AlGaN emitter and SiC base/collector hold the promise of high-power and high-frequency operation due to lower impact ionization coefficients and higher breakdown voltages. Further, Silicon Carbide has an indirect bang gap, and a large lifetime of minority carriers compared to most other compound semiconductors, which tend to have direct band gaps. This reduces the base recombination factor when the base is made from SiC, and helps to achieve higher overall current gain. Spontaneous and piezoelectric polarizations of the order of 1013 electrons per cm2 exist in wurtzite wide band-gap semiconductors. This has a non-trivial effect on band profile, charge transport and overall device characteristics since the polarization-induced charges are of the same order of magnitude as the total dopant charge content of critical device layers, and can significantly affect the amount of mobile charge depletion or accumulation in these layers. We calculate the effect of this polarization for both very thin pseudomorphic emitters and for relaxed emitter structures. We present calculations for the cases of Si-face and C-face SiC, since the signs of polarization-induced charges are different for the two cases. The intrinsic base resistance near emitter flat-band conditions is changed by a factor of 10 depending on the alloy composition of the emitter and the polarity of growth. The maximum frequency of oscillation under emitter flat-band conditions can also be modulated by the polarization-induced charges by up to 60%. Our calculations show that the technologically less prevalent C-face SiC can give a higher advantage for frequency response, especially when the emitter thickness is larger than the critical thickness.

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