SBIR Phase II: Innovative Germanium-based Short Wavelength Infrared Image Sensors

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is to allow a greater number of organizations, businesses, and individuals to access shortwave infrared (SWIR) imaging technology. Modern SWIR technology has existed for more than 40 years, but its expense has limited its use to the military and large corporations; this project is grounded in the belief that when everyone has access to SWIR technology, the benefits to society are exponential. SWIR image sensors have potential applications in food safety analysis (e.g., identifying harmful adulterated foods and revealing sub-surface flaws in produce), manufacturing (e.g., sorting), security (e.g., night vision), medical sensing (e.g., vein mapping and blood oxygenation monitoring), and the automotive field (e.g., night/inclement weather vision systems and for self-driving vehicles). A low-cost sensor will open the SWIR imaging market to players in these fields who have so far been shut out due to price. In addition, a low-cost, high-quality sensor will also make SWIR imaging directly available to the general public for the first time ever in the form of a SWIR camera smartphone add-on, establishing a new market for SWIR imaging. This Small Business Innovation Research (SBIR) Phase II project will produce low-cost germanium (Ge)-based shortwave infrared (SWIR) image sensors with features superior to those of currently available SWIR sensors. The research objective is to resolve issues of resolution, power usage, size, and sensitivity that limit advancement in the SWIR imaging field. This project will address these problems by utilizing a unique Ge-based SWIR sensor structure. In addition, a monolithic method of integrating the image sensor material onto the Si readout integrated circuit will be pursued. This will enable precise alignment of the readout integrated circuit and the imaging device, which will lead to smaller pixel size and better resolution. Finally, issues of power use and sensitivity will be addressed through an innovative structure called Gate-controlled Charge Modulate Device. Research will focus on refining and improving the fabrication processes necessary to reliably produce low-cost, high-quality Ge-based SWIR image sensors.