SpecEES:Heterogeneous Integration Techniques for Frequency-Conversion and Access to the Submillimeter Spectrum

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

The submillimeter-wave region of the electromagnetic spectrum is crucial to fundamental scientific inquiry and progress in fields such as radio astronomy, atmospheric physics, and remote sensing. Moreover, new and emerging device concepts promise to open this largely-inaccessible spectrum to further scientific study as well as important engineering applications in imaging, non-destructive test and evaluation, and extremely high data-rate communications. The lower portion of the submillimeter-wave band (100 GHz to 500 GHz) remains a vast and untapped resource for wireless data transfer. Although limitations imposed by atmospheric attenuation make this spectral range unsuitable for long-distance wireless data transfer, these frequencies can potentially be used for super-high-speed wireless data transfer to augment and expand the performance of existing RF and microwave communications. To enable access to this submillimeter-wave band, this project focuses on the development of fabrication processes that will facilitate heterogeneous integration of compound semiconductors (e.g., gallium arsenide or indium phosphide) as well as methods to efficiently connect submillimeter-wave circuits with silicon CMOS integrated circuits. The intellectual merit in developing such processes lies in their potential to improve understanding of the fundamental science of electrical/mechanical interfaces as well as the practical issues involved with applying this knowledge to creating new wireless technologies. The objective of this project is to create the device, interface, and front-end infrastructure needed to extend the capabilities of existing wireless systems to access the submillimeter-wave region of the spectrum. To achieve this goal, the research effort focuses on three primary tasks: (1) robust methods for heterogeneous integration of gallium arsenide (or other III-V semiconductor materials) onto high-resistivity silicon carrier-substrates for interconnection with silicon CMOS backend electronics, (2) design and implementation of low-parasitic interfaces between CMOS chips and III-V submillimeter-wave front-ends, and (3) development of power-efficient up- and down-converters for accessing the submillimeter-wave region. The work proposed here represents an initial and necessary step towards developing an infrastructure that overcomes the limitations of current approaches in utilizing submillimeter-wave technology for wireless applications. Moreover, the research to be undertaken will address fundamental issues in heterogeneous integration, micromachining, and high-performance interfaces. These topics comprise an important area of work that will impact a wide array of engineering fields including microelectronics, microelectromechanical systems, electromagnetics, and communications.