Title :
Study on collector design of AlGaAs/GaAs heterojunction bipolar transistors by two-dimensional simulation
Author :
Horio, K. ; Iwatsu, Y. ; Oguchi, A. ; Yanai, H.
Author_Institution :
Shibaura Inst. of Technol., Tokyo, Japan
Abstract :
The cutoff frequency (fT) characteristics of NPN-n+ AlGaAs/GaAs HBTs (heterojunction bipolar transistors) with various n- collector structures are studied by two-dimensional simulation. It is shown that the transit time in the collection depletion layer becomes a more important factor than the collector charging time in the high current region. Therefore, a thinner n- collector layer with higher doping density is desirable for achieving higher cutoff frequency. The introduction of a semi-insulating external collector is effective in improving cutoff frequency characteristics in the relatively low current region. However, it is noted that it may lead to the earlier fall of cutoff frequency due to a high injection effect
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; semiconductor device models; simulation; AlGaAs-GaAs; HBTs; collection depletion layer; collector design; cutoff frequency characteristics; doping density; heterojunction bipolar transistors; n- collector structures; semi-insulating external collector; transit time; two-dimensional simulation; Capacitance; Charge carrier processes; Cutoff frequency; Delay effects; Doping; Gallium arsenide; Heterojunction bipolar transistors; Photonic band gap; Poisson equations; Protons;
Conference_Titel :
Bipolar Circuits and Technology Meeting, 1990., Proceedings of the 1990
Conference_Location :
Minneapolis, MN
DOI :
10.1109/BIPOL.1990.171161
