InAs/GaSb superlattice focal plane arrays for high-resolution thermal imaging

Author(s):  
Robert Rehm ◽  
Martin Walther ◽  
Johannes Schmitz ◽  
Joachim Fleißner ◽  
Frank Fuchs ◽  
...  
1996 ◽  
Vol 450 ◽  
Author(s):  
E. Michel ◽  
H. Mohseni ◽  
J. Wojkowski ◽  
J. Sandven ◽  
J. Xu ◽  
...  

ABSTRACTIn this paper, we report on the growth and fabrication of InSb detectors and Focal Plane Arrays (FPA's) on (100) Si, Al203, and (100) and (111) GaAs substrates for infrared (IR) imaging. Several advantages result from using GaAs, Si, or Al203. First, InSb FPA's on these materials do not require thinning as with detectors fabricated from bulk InSb. In addition, these substrates are available in larger sizes, are semi-insulating (GaAs and sapphire), and are less expensive than InSb.Optimum growth conditions have been determined and discrete devices have been fabricated on each substrate material. The structural, electrical, and optical properties were verified using x-ray, Hall, photoresponse, and photoluminescence (PL) measurements. Measured x-ray Full Widths at Half Maximum (FWHM) were as low as 55 and 100 arcsec for InSb epilayers on GaAs and Si, respectively. Hall mobilities were as high as 128,000, 95,000 and 72,000 cm2/V-sec at 200 K, 77 K, and room temperature, respectively. In addition, 77 K PL linewidths were as low as 18, 20, and 30 meV on GaAs, Si, and sapphire substrates respectively, well below the 48 meV value previously reported in the literature.In collaboration with Lockheed Martin Fairchild Systems (LMFS), IR thermal imaging has been obtained from InSb FPA's on GaAs and Si substrates. This is the first successful IR thermal imaging from heteroepitaxially grown InSb. Because of the high quality substrates, larger areas, and higher yields, this technology is very promising for challenging traditional InSb FPA hybrid technology.


2006 ◽  
Vol 14 (1) ◽  
Author(s):  
R. Rehm ◽  
M. Walther ◽  
J. Schmitz ◽  
J. Fleißner ◽  
F. Fuchs ◽  
...  

AbstractThe first fully operational mid-IR (3–5 μm) 256×256 IR-FPA camera system based on a type-II InAs/GaSb short-period superlattice showing an excellent noise equivalent temperature difference below 10 mK and a very uniform performance has been realized. We report on the development and fabrication of the detecor chip, i.e., epitaxy, processing technology and electro-optical characterization of fully integrated InAs/GaSb superlattice focal plane arrays. While the superlattice design employed for the first demonstrator camera yielded a quantum efficiency around 30%, a superlattice structure grown with a thicker active layer and an optimized V/III BEP ratio during growth of the InAs layers exhibits a significant increase in quantum efficiency. Quantitative responsivity measurements reveal a quantum efficiency of about 60% for InAs/GaSb superlattice focal plane arrays after implementing this design improvement.


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