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Proceedings Paper

Monolithically Integrated Two-Dimensional Arrays Of Optoelectronic Threshold Devices For Neural Network Applications
Author(s): J. H. Kim; S. H. Lin; J. Katz; D. Psaltis
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Paper Abstract

We report on the design, fabrication, and testing of a 10x10 monolithic integrated two-dimensional array of AlGaAs optoelectronic threshold elements (optical neurons) for neural network applications. The array has dimensions of 5x5 mm2 and the neuron has dimensions of 250x250 μm2. Each neuron consists of a light emitting diode (LED) driven by a double-heterojunction bipolar transistor, which is driven by the output of a double-heterojunction phototransistor. We demonstrated the partial functional operation of 2-D array of optical neurons by independently characterizing each device on the integrated circuit. DC current gain of 30 was obtained at the collector current density of 1.0x103 A-cm-2 with the emitter area of 3.5x10-5 cm2 in a single transistor without spacer layers. The output power densities of the light emitting diodes were about 1.0x102 W-cm-2 at a current of 20 mA. However, the overall integrated structure showed the semiconductor controlled rectifier characteristics with the breakover voltage of 75 V, the holding current of 10 mA at the holding voltage of 25 V, and the reverse breakdown voltage of 60 V. This is attributed to the parasitic p-n-p transistor that exists due to the sharing of the same n-AlGaAs collector between the transistors and LED.

Paper Details

Date Published: 22 June 1989
PDF: 10 pages
Proc. SPIE 1043, Laser Diode Technology and Applications, (22 June 1989); doi: 10.1117/12.976352
Show Author Affiliations
J. H. Kim, California Institute of Technology (United States)
S. H. Lin, California Institute of Technology (United States)
J. Katz, California Institute of Technology (United States)
D. Psaltis, California Institute of Technology (United States)

Published in SPIE Proceedings Vol. 1043:
Laser Diode Technology and Applications
Luis Figueroa, Editor(s)

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