Optimization of fabrication processes of the mesa-type GaAs:Te blocked-impurity-band detector
In this work, the device structure of the mesa-type GaAs:Te blocked-impurity-band detector was designed. The fabrication processes were presented briefly, and optimization of the fabrication processes was investigated. A 3-micron-thick SiO2 film was deposited as resist to substitute for photoresist in the 50-micron-deep mesa etching process. In addition, a bi-layer photoresist lithography technique was adopted to optimize the process of electrode fabrication. It is demonstrated that the device quality can be improved significantly after optimization.
Development of Si:As impurity band conduction (IBC) detectors for mid-infrared applications
Si:As Impurity Band Conduction (IBC) detectors offer many significant advantages over other conventional photon detectors utilized for the infrared. SiAs offer excellent spectral response out to 28 μm with dark current in the 0.01e/second range at 7K over a wide bias range with no tunneling limitations. In addition, because of the perfect thermal match between the Si:As IBC detector and the readout IC (ROIC), hybrids formed by mating Si:As IBCs and ROICs are mechanically stable and have no hybrid reliability problems. Since Si:As IBC detectore are fabricated on readily available Si substrates, large formats are realizable. Si:As IBC detectors have been under development since the mid 80's at Raytheon Vision Systems (RVS). Under the NSAS SIRTF program, a 256 x 256 Si:As array was developed and successfully integrated into the SIRTF IRAC instrument. This same array is also utilized in the ASTRO-F IRC instrument. Both missions will be launched shortly and provide a significant improvement in our ability to measure the spectral signatures of solar type stars and galaxies at high redshifts under very low background conditions in space. Under the NASA Origins program, in collaboration with NASA Ames Research Center (ARC), RVS developed a high performance 1024 x 1024 Si:As IBC array. This array was tested at Ames Research Center. This paper will review the progress of Si:As IBC development at RVS, present test data from ARC, and discuss the more recent developments in Si:As IBC detectors for the JWST MIRI instrument and future missions such as SPICA, TPF, FIRST and DARWIN.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.