A Methodology to Characterize the Low-Frequency Noise of InP Based Transistors

This paper describes a methodology to measure the low-frequency noise of InP-based transistors. These transistors have demonstrated transition frequencies (ft) greater than 200 GHz, generally achieved at current densities in excess of 200 kA/cm2. Depending on the DC current gain, this may represent base currents of some mA. For the first time, curves of Sib, Sic and Sibic for base currents of up to 3 mA are demonstrated, in excellent agreement with those obtained from one-port measurements. This is only possible with an accurate experimental characterisation of the small-signal parameters of the transistor, which are frequency-dependent due to self-heating.