Micromachined photoconductive electric field mapping probe for the measurement of picosecond pulse propagation

The mapping of the electromagnetic fields above a microwave circuit can be of great importance in detecting desirable and undesirable interactions of the circuit with its surroundings and failure diagnosis of microelectronic integrated circuits. As a time-domain pulse measurement technique, photoconductive sampling can measure picosecond electric fields when the switch is positioned in free-space as well as picosecond potential pulses. In this paper, we develop a photoconductive electric-field probe with less than a picosecond temporal resolution and μm spatial resolution for picosecond pulse propagation properties measurement. The probe was fabricated using a semiconductor micromachining process based on low-temperature-grown GaAs (LT-GaAs) lift-off thin film technique (ELO)