CHARGE ACCUMULATION EFFECTS AND MICROWAVE-ABSORPTION OF COPLANAR WAVE-GUIDES FABRICATED ON HIGH-RESISTIVITY SI WITH SIO2 INSULATION LAYER

Microwave attenuation of coplanar waveguides fabricated on high-resist ivity silicon substrates with SiO2 insulation layer is investigated fr om 10 GHz up to 600 GHz by optoelectronic time-domain measurements. Th ey are performed directly on the wafer employing a freely positionable photoconductive switch for picosecond-electric-pulse injection and an electro-optic crystal for pulse detection. The attenuation is signifi cantly altered over the whole frequency range by free-carrier absorpti on resulting from inversion and accumulation effects at the Si/SiO2 in terface. (C) 1995 American Institute of Physics.