Abstract

Microstrip transmission lines consisting of a narrow center line and an extended groundplane are the most commonly used device interconnections in millimeter-wave integrated circuits. Typically, the ground plane of a microstrip line is located on the backside of the roughly 500 µm thick semiconductor wafer that carries the circuit elements. For frequencies above 10 GHz, this simple scheme can lead to a limitation of the useful bandwidth of ultra-high-speed electronic circuits because dispersion can significantly distort the electrical pulses propagating on the microstrip interconnect [Goossen, 1989]. Recently, it has been proposed to use buried silicide layers as groundplanes for microstrip lines in silicon based circuits [Goossen, 1990]; the resulting reduction in the separation of the center conductor and the ground plane should push the onset of the dispersion to frequencies above the range of interest. For a separation of 10 pm the dispersion should be negligible for frequencies up to 500 GHz. Here, we test this concept by studying the propagation of 100 GHz bandwidth electrical pulses on microstrip lines that have been fabricated on silicon wafers with buried and with conventionally formed groundplanes.

© 1991 Optical Society of America