Properties Of Bipolar Transistors Research Articles

Topology investigation for the low frequency noise compact modelling of bipolar transistors

The low frequency noise (LFN) properties of bipolar transistors are investigated in terms of equivalent input referred, partially correlated noise generators. These properties are studied as a function of the intrinsic noise sources and of the small-signal model topology. Topology invariance and identity properties are identified and their practical implications on the LFN modelling of bipolar transistors are assessed.

Analysis of low noise, bipolar transistor head amplifiers for high energy applications of silicon detectors

The properties of bipolar transistors as input devices for low noise head-amplifiers for high energy applications of silicon detectors are discussed. Theoretical and experimental investigations have been carried out for three different configurations of head amplifiers. The results show that under the particular constraints of high energy experiments, the bipolar transistor has some features that make it competitive, if not even superior to the so far widely employed junction field-effect transistors. These constraints are the short processing times that have to be used to cope with the very high counting rates and the large detector capacitances of some experiments. It emerges from the analysis that the bipolar transistor appears to be an attractive input device for head amplifiers intended for large acquisition systems associated with silicon detectors.

Some aspects of LEC transistor behaviour

Some properties of bipolar transistors with low emitter concentrations are investigated both theoretically and experimentally. It turns out that the base current of LEC transistors at medium and high injection levels is the same as in double diffused transistors and can be explained by Auger recombination in the emitter n + region. The cut-off frequency f T is rather low, due to extra charge storage in the lightly doped emitter region. Small n + emitter areas, surrounded by a p-ring may introduce anomalies such as kinks in the ( cb, V be ) characteristics and negative resistances.