Title :
A thin film indium gallium arsenide focal plane array for visible and near infrared hyperspectral imaging
Author :
Cohen, Marshall J. ; Lange, Michael J. ; Ettenberg, Martin H. ; Dixon, Peter ; Olsen, Gregory H.
Author_Institution :
Sensors Unlimited Inc., Princeton, NJ, USA
Abstract :
Indium gallium arsenide (InGaAs) focal plane arrays (FPAs) have proven useful in a wide variety of scientific, commercial, and military applications ranging from near infrared spectroscopy to night vision imaging. In a two-dimensional InGaAs FPA, an InGaAs photodiode array is hybrid-integrated to a silicon CMOS readout integrated circuit using indium bump-bonding techniques. The array is backside-illuminated with a long wavelength cutoff at 1.7 μm due to the bandgap of the In0.57Ga0.53As active layer and a 0.9 μm "cut-on" due to absorption in the indium phosphide (InP) substrate. We report a novel heteroepitaxial structure and process technology in which a thin (⩽ 0.3 μm) InP "common cathode" is inserted under the InGaAs active layer. The InP substrate is removed after the FPA has been hybrid-integrated. The result is a thin (< 5 μm) photodiode array membrane supported on a two-dimensional matrix of indium columns. The FPA exhibits photoresponse from 0.5 μm in the visible to the 1.7 μm InGaAs cutoff and is ideal for broad-band imaging spectroscopy or hyperspectral imaging
Keywords :
III-V semiconductors; focal planes; gallium arsenide; indium compounds; integrated optoelectronics; optical arrays; optical fabrication; p-n heterojunctions; photodiodes; semiconductor epitaxial layers; thin film devices; 0.3 mum; 0.5 mum; 0.9 mum; 1.7 mum; In0.57Ga(0.53)As active layer; In0.57Ga0.53As; InGaAs; InGaAs active layer; InGaAs cutoff; InGaAs photodiode array; InP; InP substrate; Si; Si CMOS readout integrated circuit; backside-illuminated; bandgap; broad-band imaging spectroscopy; commercial applications; common cathode; focal plane array; focal plane arrays; heteroepitaxial structure; hybrid-integration; hyperspectral imaging; indium bump-bonding techniques; long wavelength cutoff; military applications; near infrared hyperspectral imaging; near infrared spectroscopy; night vision imaging; photodiode array membrane; photoresponse; process technology; scientific applications; two-dimensional matrix; visible hyperspectral imaging; Hyperspectral imaging; Indium gallium arsenide; Indium phosphide; Infrared spectra; Night vision; Optical imaging; Photodiodes; Silicon; Substrates; Transistors;
Conference_Titel :
LEOS '99. IEEE Lasers and Electro-Optics Society 1999 12th Annual Meeting
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-5634-9
DOI :
10.1109/LEOS.1999.811948
