Low-cost Mid-wave Infrared Focal-Plane Arrays through Direct-on-Read Out Integrated Circuit Detector Fabrication

RT&L FOCUS AREA(S): Autonomy;Microelectronics TECHNOLOGY AREA(S): Materials / Processes;Sensors The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Develop new detectors, bonding methods, or fabrication techniques for mid-wave infrared (MWIR) focal plane arrays that enable lower cost infrared imaging for navigation, object detection, collision avoidance, and force protection. DESCRIPTION: Electro-Optic and Infrared (EO/IR) sensors are used in a wide variety of applications and missions such as long-range detection and identification of objects, seeing at night, and wide area surveillance. Although infrared offers superior imaging in most scenarios, visible sensors are more proliferated than IR due to the dramatically lower cost and higher pixel resolution available. IR sensors have higher costs compared to visible because of many system factors; this SBIR topic proposes to solve one of those factors: the focal plane array (FPA). The MWIR imaging band of 2.8 um to 5 um is used across the Naval forces for imaging targets in a wide range of atmospheric conditions. The goal is to develop novel MWIR FPA materials or processes to achieve > 20x cost reduction over existing MWIR FPAs. In order to get an image out of the IR FPA, die-to-die bonding of the FPA to a read out integrated circuit (ROIC) is performed creating a sensor chip assembly (SCA). Multiple infrared imaging technologies are used today for the FPA [Ref 1] and most are now available at higher operating temperatures (HOT) (e.g., above 110 K). All of the highest performing FPAs are made from either group III-V or II-VI semiconductors [Ref 1, 2]. The IR-absorbing material chosen sets the limit on overall FPA size, pixel size, and cost. Some of these factors are directly related to the substrate (e.g., size and cost), while others are material and processing specific (e.g., pixel size). No matter what FPA material is chosen, the ROIC is always made in (Silicon (Si) due to the low-cost manufacturing and superior electronics properties. To accomplish the goal of a low-cost MWIR FPA, various strategies might be explored. One such method might be the use of IR-absorbing semiconductors that are compatible with Si-complementary metal oxide semiconductor (CMOS) processes. In this approach the absorber would be directly deposited (i.e., grown) on the Si wafer containing the ROIC-enabling large-scale batch processing directly on 200 mm or 300 mm Si CMOS wafers. Multiple material systems within this direct growth area have been explored previously that could be applied to this topic. Possible research directions include, but are not limited to, Group IV materials [Ref 3], III-V direct growth [Ref 4], and quantum dots [Ref 5]. Another such method outside of direct growth on Si is novel direct bonding methods of an FPA wafer to the Si ROIC. In this approach, the FPA active absorber material is grown on III-V or II-VI substrates, then subsequently bonded to the Si ROIC. All solutions should address yield and the ability to scale down to smaller pixels to meet future large format sensing requirements. The solution should be a drop-in replacement to existing MWIR SCAs and thus should not require significant deviation in design to existing MWIR optics. If the solution requires cooling, then industry standard integrated dewar cooler assemblies (IDCA) or thermoelectric coolers should be used to maximize backwards compatibility. End of program deliverable design characteristics: Specific detectivity (D*) within the 3 um to 5 um band: above 10^11 Jones [normalized to 2*pi field of view (FOV) and 300 K background] Noise equivalent temperature difference (NETD): below 25 mK Quantum efficiency (QE) within the 3 um to 5 um band: shall be no less than 20% of the peak QE Peak QE: shall be between 3 um and 5 um Detector cooling: >= 110 K Pixel size: