2048×2048 HgCdTe focal plane arrays for astronomy applications

Rockwell is developing the world's largest HgCdTe infrared focal plane array (FPA) for astronomy and low background applications. The format of the device is a hybrid 2048x2048 with a unit cell size of 18 μm x 18 μm. SWIRdetectors with a spectral response of 0.85 μm to 2.5 μm have been processed on liquid phase epitaxy (LPE) HgCdTe on sapphire substrates. The MWIR detectors with a spectral response of 0.4 pm to 5 μm will be processed on molecular beam epitaxy (MBE) HgCdTe on CdZnTe substrates. 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. Novel hybrid fabrication techniques will be used to demonstrate the FPA. 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: dark currents of 75% across the spectral band, and noise levels of 40K for the MWIR band. The status of the 2048x2048 detector arrays and FPAs are discussed.