Advanced FPA Products

ROIC design – BAE Systems designs read out integrated circuits (ROICs) for use in focal plane arrays (FPAs). These custom, mixed-signal integrated circuits interface between the detectors and the FPA, and perform signal processing functions; typical ROIC functions include integration and multiplexing.

BAE Systems has pioneered a number of advanced processing features such as automatic gain, subframe averaging, gamma noise suppression, and analog-to-digital conversion. ROICs support infrared, ultraviolet, visible, and ultrasound FPAs.

Material growth – More than 20 years of technology development have gone into BAE Systems' liquid phase epitaxy (LPE) growth technology, resulting in excellent uniformity with low dislocation densities. The LPE also contains a low density of macrodefects.

Focal plane array assembly – BAE Systems designs and fabricates state-of-the-art large-area focal-plane products (432 x 432 pixels at a 36 micron pitch – SW and MW). BAE Systems’ hybridization equipment can cold-weld using forces up to 100 Kg.

The current cooled FPA marketplace calls for larger FPAs; BAE Systems will ensure its presence in the large FPA market in the years ahead using its superior hybridization to improve all facets of LPE and individual array fabrication

Back-illuminated focal plane arrays – BAE Systems’ back-illuminated focal planes have a distinct advantage over other approaches because of its silicon ROIC, manufactured independently from the HgCdTe array. Thus, the process steps for the ROIC and the HgCdTe do not have to be compatible. After processing, the two parts are "flip-chip" hybridized through cold-welding of indium interconnect "bumps." During hybridization, the ROIC and the HgCdTe array are aligned, and the two parts are brought together under high force (up to 100 kgm). This fusion causes the indium metal, previously deposited on the two parts, to intermix and form a mechanical and electrical connection among the individual pixels on the array and the ROIC.

Electrical test – BAE Systems has a complete ROIC and FPA test capability that employs standard test stations. These stations include all the electronics necessary to generate clocks, control signals, biases, and power for FPAs and data acquisition with 14 or 16 bits. Wide-aperture and high-temperature blackbody sources are available for standard infrared FPA testing. Special purpose stations allow spot testing and spectral response testing of FPAs. Probe stations are available for probe testing ROIC wafers. Standard dewars are available for FPA testing, from 300 K to 40 K or below under high- or low-irradiance conditions.