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 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.
| Original language | English |
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| Pages | 195-198 |
| Number of pages | 4 |
| Publication status | Published - 1990 Dec 1 |
| Event | Proceedings of the 1990 Bipolar Circuits and Technology Meeting - Minneapolis, MN, USA Duration: 1990 Sep 17 → 1990 Sep 18 |
Other
| Other | Proceedings of the 1990 Bipolar Circuits and Technology Meeting |
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| City | Minneapolis, MN, USA |
| Period | 90/9/17 → 90/9/18 |
ASJC Scopus subject areas
- Engineering(all)