ED Characterisation
LOW-FREQUENCY DYNAMIC I/V CHARACTERISATION of III-V FETs
Low-frequency dispersion (due to "traps" and thermal effects) plays a major role in III-V electron device characterisation and modelling., as it cause important and non-negligible deviations between static and dynamic I/V characteristics.
Pulsed I/V measurement setups have been widely adopted to characterise the I/V transistor behaviour. Pulsed setups however are very expensive and their use is made complex by the interaction of relatively large-bandwidth pulsed signals with system cables, bias tees, etc.. Moreover, the device is characterised in a regime (pulsed) which is strongly different from actual operating conditions (sinusoidal or distorted sinusoidal).
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As an alternative to pulsed measurement system different setups for the low-frequency measurements of dynamic I/V transistor characteristics under sinusoidal excitations have been developed which are based on incident and reflected waves acquisition through directional couplers and sampling oscilloscopes. A first single-source setup exploits different resistive terminations to characterise the electron device. |
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More recently a powerful two-source setup has been developed and automated. This measurement system represents a low-frequency load-pull (LFLP) setup which can be effectively exploited to obtain an in-depth characterisation of dynamic I/V characteristics under different operating conditions.In the most recent version of the setup also harmonic components can be controlled. The LFLP setup is being successfully adopted in the context of device characterisation and reliability evaluation, transistor modeling as well as power amplifier design.
