THz Electronics Design in Nanometer CMOS

With the continuing scaling of CMOS nodes and increases in operation frequency of RF integrated circuits, there is more interest in the terahertz (THz) spectrum than ever before. Ranging from 300 GHz to 3 THz, the THz or sub-mm wave spectrum lies between the domains of optics and electronics on the frequency scale, resulting in a wide range of possible applications. Non-destructive quality control of packaged goods, as well as 3D imaging and accurate distance, speed and acceleration measurements are among the potential of the sub-mm wave spectrum. Due to the interaction of THz waves with different chemical components, spectroscopy applications such as cancer detection, cavity detection for dentistry or detecting the water contents (and ripeness) of fruits and vegetables are possible.

Most commercially available THz products are based on III-V technologies, and while this is acceptable for low-volume, high-cost niche markets, the preferred technology for mass-produced THz chips would be CMOS. The main roadblock preventing a fully integrated CMOS THz circuit block is the technology-specific fmax, preventing fundamental oscillators and power amplification above this frequency. Radiation of the generated THz proves also to be of major concern, as the need for efficient on-chip antennas rises.

This research focuses on the design of THz CMOS circuits above fmax using harmonics of sub-fmax signals, and integrates the circuits with on-chip antennas for compact THz radiation sources and detectors. Investigations into the possible applications of THz imaging are also undertaken using our own in-house designed chips.