nBn HOT-MW and SWIR detectors on Si using interfacial misfit arrays
Abstract
The project goal is to develop interfacial misfit (IMF) arrays to integrate III-V semiconductor nBn mid-wave infrared (MWIR) detectors with large-format Si substrates. The MWIR region of the electromagnetic spectrum is critically important for naval defense applications including target tracking and identification in all weather conditions. The Navy is therefore eager to deploy widespread MWIR imaging and detection. Currently, the best low-noise MWIR detectors and focal plane arrays (FPAs) are based on the nBn device architecture that we first pioneered in 2006. nBn MWIR detectors are made from III-V semiconductor heterostructures grown on GaSb substrates. The drawback is that GaSb substrates are extremely expensive and are only available up to 6# in diameter, two factors limitingthe Navy#s ability to implement large, cost effective MWIR FPAs across the fleet. The ability to grow III-V nBn MWIR detectors directly on Si wafers would overcome both of these issues with GaSb substrates. Si substrates are two orders of magnitude cheaper than GaSb substrates of the same size, and are available up to 12# in diameter. What is more, the use of large format Si wafers allows oneto take advantage of the high-volume manufacturing processes developed by the electronics industry. The problem is that due to differences in lattice constant, polarity, and thermal expansion, integrating III-V semiconductors with Si substrates is a long-standingchallenge.We propose to overcome this challenge through the use of IMF arrays. We can form these periodic arrays of in-plane misfitdislocations right at the III-V/Si interface by selecting very specific conditions for molecular beam epitaxy. IMF arrays efficiently relieve the large strain between the III-V and the Si, without generating a high density of threading dislocations. The result ishigh-quality III-V growth on Si without the need for prohibitively thick buffer layers or pre-growth substrate patterning. Since the IMF arrays self-assemble, this approach is inherently scalable, presenting the Navy with a viable route to grow low-noise MWIR nBnFPAs on large format, 8#12# Si wafers. In parallel, we will also explore the feasibility of also integrating III-V SWIR and LWIR detectors with Si wafers using modified IMF techniques.To meet the project goal, we will 1) Create high-quality GaSb buffers on AlSb/Si(001) IMF virtual substrates; 2) Synthesize and test III-V nBn devices on Si for specific MWIR bands; 3) Explore IMF-based SWIR andLWIR devices on Si using IMF arrays; and contingent on funding 4) Fabricate and test FPAs from III-V nBn detectors grown on Si. We are well-qualified to perform this work. Our research team consists of PI: Paul Simmonds (Tufts), an expert in dissimilar materials integration by molecular beam epitaxy; and unfunded industry advisor Shimon Maimon (NetzVision), the original inventor of the nBn detector for low-noise FPAs. If successful, the anticipated research outcome would be to provide the Navy with high-operating temperature, low-noise MWIR nBn detectors on 3# substrates at significantly lower cost than is currently possible. If funding is sufficient,we will develop FPAs from this material and benchmark their performance. In doing so, we will establish a trajectory for future scaling of this technology to 8#12# Si platforms. By overcoming the GaSb substrate bottleneck, Si-based nBn devices could revolutionizethe thermal imaging industry. These outcomes are highly relevant to the Navy#s efforts to deploy widespread IR detection and imaging and align squarely with N00014-24-S-B001 in the EO/IR Sensors technology area. Although certainly an ambitious project, given our expertise in the MBE of IMFs, nBn detector design and fabrication, key university and industry partnerships, and access to world-class facilities, we are confident of achieving our technical objective of producing scalable III-V IR detectors on Si.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 11, 2024
- Source ID
- N000142412276
Entities
People
- Paul J. Simmonds
Organizations
- Office of Naval Research
- Tufts University
- United States Navy