Quantum Cascade Lasers (QCLs) are one of the most versatile sources of radiation in the mid-infrared range and have found applications in a variety of fields. Despite their widespread adoption, one of the main hurdles holding QCLs back from large volume manufacturing is the large cost of ownership. While QCLs, like most semiconductor devices based on III-V compounds, can leverage the economies of scale typical of semiconductor manufacturing, and therefore lower production cost at wafer and chip level, it is at the testing and packaging stages of QCL production that most of the cost can build up and not scale as easily in large volumes. One of the most time-consuming steps during the post-fabrication testing and packaging process is device burn-in. Burn-in generally consists in running the devices in controlled conditions deemed representative of the actual operating specs in the field for a number of hours. This is done in order to screen out possible early degradation issues that may lead to costly device replacement after system installation is complete. Notwithstanding the importance of this issue, up till now there are no recognized industry standards for device burn-in qualification procedures and there are no proven models for laser degradation to support such procedures. Optimizing early screening of defective devices by improved burn-in procedures is likely going to reduce post-fabrication costs (testing, packaging, installation, etc.) which in large volume manufacturing typically represent the largest portion of production costs. A long burn-in procedure (i.e. 100hrs or more) can help reduce the rate of rejection of QCLs from ~20% straight out of the wafer to less than 2% when delivered to the customer, so a 10-fold reduction in returned product costs both for the manufacturer and for the final user. This result though, comes at the cost of a very time-consuming procedure that cannot easily be scaled up to large volumes without increasing the cost of capital equipment and production logistics. Reducing the burn-in time to a few hours, or maybe even minutes, at least for the devices most likely to fail, will unlock a great cost reduction for the manufacturer that can be passed on to the final user. The key to realizing such a dedicated burn-in procedure lays in the following main steps: Understand the failure mechanisms of high power QCLs (device degradation models) Enhance burn-in stressors that map the failure modes specific to QCLs (accelerated burn-in) Identify key screening parameters leading to early signs of degradation (quick rejection tests) In this way we can not only build a more effective burn-in procedure that can reduce the rejection rate of finished products, but we will also be able to reject defective devices earlier in the process and therefore reduce the costs associated with testing time and facilities.
Benefit: QCLs are already deployed in the field in small quantity for applications ranging from gas monitoring to remote sensing, industrial process control, medical diagnostics, analytical tools, among others. A common barrier to acquisition of this technology is its present high cost. The current price of QCLs does not allow for small, inexpensive systems to be developed and commercialized based on this technology. With the cost reduction achieved by this proposal, QCL device prices can be reduced to below the $1,000 mark, and enable a multitude of applications only accessible via lower system costs (<$10,000) and lower operating costs due to the lower rate of returns. These applications will broaden the market addressable by QCL technology and initiate a virtuous cycle that will bring the device price even lower. The market size for high value QCL devices and systems with pricing in the $10,000 per device and $100,000 per system is in the range of $200M, i.e. an average of 1000 units sold into 2 main application domains. Lowering the cost of QCLs by a factor 5-10 will enable the commercialization of systems with a target price of $10,000, whose estimated market size is $500M-$1B, corresponding to 5-10 different applications, each with volume sales capacity of 10,000 units. A key to market acceptance for a new laser engine is to attain the same reliability as telecom lasers at comparable prices. This program will enable and make available low-cost high power QCLs in the 4A and 4B high power spectral bands. The target cost to the final user will be an order of magnitude lower than present costs (~$1k/Watt vs. ~$10k/Watt) and will enable the deployment of this technology for applications that today cannot support the present costs. In particular, this will benefit existing programs of record such as CESARS and MATADOR FNCs for SEWIP Block 4B. High power systems for IRCM applications where multi-emitter combination is required to get to the 10s of Watts power range, can be significantly affected due to the need to procure multiple devices per system, thus scaling up dramatically the total system cost. By lowering the individual chip cost we can enable the acquisition of multi-Watt laser systems at a fraction of todays price. The transition to procurement can either go through direct Phase III contract or via a Prime Contractor. We already have significant interest from several Defense contractors such as Lockheed Martin, DRS, DHPC, Forward Photonics. In addition, a number of commercial applications will benefit from the availability of low-cost high power QCLs, and will enable Adtech to leverage even more the volume manufacturing of these devices towards low-cost solutions. Examples of commercial or dual-use applications are: Lidar / remote sensing, Photoacoustic spectroscopy, Laser material processing, Assisted surgery, Optical wireless secure communications.
Keywords: Failure Analysis, Failure Analysis, quantum cascade lasers, low-cost production, Reliability Modeling, burn-in
