2048x2048 VISIBLE/INFRARED HgCdTe FOCAL PLANE ARRAYS (FPAs)

Rockwell has developed the world’s largest multiplexer for use with infrared HgCdTe and visible silicon detector arrays. The resulting FPAs are to be proposed for the Next Generation Space Telescope (NGST) program, ground-based astronomy, and other low background applications. The 2048x2048 multiplexer’s unit cell size is 18 µm x 18 µm with source follower per detector input (SFD) and 4 and 32 output amplifier selections. SWIR detectors with a spectral response of 0.85 µm to 2.5 µm have been processed on liquid phase epitaxy (LPE) HgCdTe on sapphire substrates. MWIR detectors (0.85-5.0 µm) will be processed on molecular beam epitaxy (MBE) HgCdTe on CdZnTe substrates. Response to wavelengths as low as 0.4 µm is possible with the substrate removal process and an example of this will be given. The multiplexer has been designed and fabricated at Conexant (formerly Rockwell Semiconductor Systems). Room temperature probing shows that the device is functional with excellent yield – 20%. Novel hybrid fabrication techniques have been used to construct the first engineering grade FPA, currently being tested. This HAWAII-2 device is based on the highly successful HAWAII 1024x1024 device and the performance will be similar. The ultimate performance expected from the array is: dar