MONOLITHIC OPTOELECTRONIC CIRCUIT-DESIGN AND FABRICATION BY EPITAXIAL-GROWTH ON COMMERCIAL VLSI GAAS-MESFETS

A technique for realizing large-scale monolithic OEIC's, which involve s epitaxially growing GaAs-based heterostructures on fully metallized commercial VLSI GaAs MESFET integrated circuits, has recently been rep orted, In the initial work the circuits and LED's occupied distinct ha lves of a chip, the dielectric growth window was wet-etched after circ uit fabrication, and the LED's required both n and p ohmic contacts to be formed after epitaxial growth, In this letter we report the use of standard foundry process etches to open dielectric growth windows int ermixed with circuitry and the growth of n-side-down LED's on a source /drain ion-implanted n(+) region serving as the n ohmic contact, A win ner-take-all neural circuit is demonstrated using these advances, whic h are important steps toward realizing higher levels of circuit integr ation.