Current generation QWIP detectors, although very cost effective, have relatively narrow spectral range and low quantum efficiencies. Tactical operation is generally limited to a single spectral band. These limitations arise from the design approach and restrict
applications to those that can tolerate these performance limitations.
Using recent device design improvements, a novel material, and special processing approaches, High Quantum Efficiency Dual Band C-QWIP detectors are currently being developed. These are expected to overcome traditional limitations in the QWIP design approach and deliver extremely high performance.
In the first phase of the program, single color LWIR and VLWIR C-QWIP FPAs in large (1024x1024) format will be demonstrated with targeted peak quantum efficiency of 35%, and correspondingly high BLIP operating temperatures. In the next phase of the program, the team will continue to improve QE towards 50% with conversion efficiency of 75%, and demonstrate dual band MW/LW FPAs. The detector gain will be optimized for operation in either low background or high background applications. These goals will
be accomplished using highly producible/low cost materials and processes. System considerations include ROIC well capacity, noise performance, as optics configuration and other concerns will be addressed. A robust design for high performance in a variety
of applications will be shown.
This work is being performed by the Army Research Laboratory (ARL) and L-3 Cincinnati Electronics (CE), with funding provided by the Missile Defense Agency.
The evolution of InSb Focal Plane Arrays (FPAs) at L-3 Communications Cincinnati Electronics (L-3 CE) has resulted in large format, high reliability, and high yields for 256x256, 640x512, 1Kx1K and even 2Kx2K formats using our patented front-side illuminated, reticulated pixel design. Baseline processes matured at 30um pitch and gradually were made producible at 25um pitch. Recent progress in process technology, specifically dry etch plasma processes and photolithography tools, has created a new set of processes/design capabilities which enable 15um pixel pitch FPAs, thus allowing us to develop a 15um pitch FPA with 4 times as many pixels, in the same foot print as the previous 30um pitch designs. We have developed a new 15um pitch, reticulated pixel design, implemented on a 512x512 format, which can then be sized into larger arrays, similar to the evolution that occurred on 30um pitch FPAs. As unit cell dimensions shrink by a factor of two, both the feature size and the alignment tolerances begin to limit optical fill factor. Addition of a novel micro-optic design, which optimizes signal collection to near 100% efficiency while maintaining near theoretical pixel MTF, will be presented.
CMC Electronics Cincinnati (CMC) is now in production on 1Kx1K InSb focal plane arrays (FPAs), and continuing efforts on a third production run of 2Kx2K large format IR FPAs. These FPAs are based on our unique reticulated InSb architecture that has been shown to be inherently scalable across format size while maintaining performance properties. Performance in the 10mk to 15mk NETD range will be shown. The design and fabrication of these advanced FPAs has challenged the state of the art in fabrication processing, testing, and qualification of both InSb detectors and silicon ROICs. Program sponsored manufacturing improvement activities, as well as CMC internal R&D, continue to improve both the yields and the performance characteristics of these large arrays. The latest yield, operability, and performance data will be shown. Data will be drawn from a population of approximately 30 2Kx2K FPAs and 50 1Kx1K FPAs. A novel approach to rapid thermal cycling FPAs will we described and recent developments that enable the fabrication of reticulated, smaller pixel pitch devices and practical Ultra Large Format FPAs with additional capability and features will be discussed.
CMC Electronics Cincinnati (CMC) is now in production on 1Kx1K InSb focal plane arrays (FPAs), and continuing efforts on a third production run of 2Kx2K large format IR FPAs. These FPAs are based on our unique reticulated InSb architecture which has been shown to be inherently scalable across format size without losing performance properties. Current offerings range from 256x256 to 2Kx2K formats ranging in between 30um and 20um pixel pitch, with 15um pixel pitch FPAs in development. Performance in the 10mk to 15mk NETD range will be shown. The design and fabrication of these advanced FPAs has challenged the state of the art in fabrication processing of both InSb detectors and silicon ROICs. Improvements made to enable large format fabrication have improved the yields and lowered the cost of smaller format FPAs as well. Program sponsored manufacturing improvement activities, as well as CMC internal R&D, continue to improve both the yields and the performance characteristics of these large arrays. This has resulted in breakthroughs in FPA size, performance, reliability and yeilds. The latest yield, operability, and performance data will be shown. Data will be drawn from a population of approximately 30 2K FPAs and 50 1K FPAs. Recent developments in smaller pixel pitch and other R&D areas will be discussed.
Last year, CMC reported performance data on the first article large format Indium Antimonide (InSb) Focal Plane Arrays (FPAs) produced at CMC Electronics Cincinnati (CMCEC). CMCEC's FPA design contains novel, thermally matched elements, which allow scaling from 256 x 256 pixel FPAs up to and including 1Kx1K and 2Kx2K FPAs as shown in Figure 1. Since a common process and wafer size is used to fabricate 256 x 256 640 x 512, 1Kx1K and 2Kx2K FPAs, the main issue in providing 2Kx2K FPAs is one of yeild improvement, not invention. Approximately 30 of these large format 1Kx1K and 2Kx2K FPAs have been built and 18 have been integrated into deliverable systems over the last year.