United States of America As Represented by the Secretary of the Air Force

Stephen M Spaziani

Kenneth Vaccaro

Eric A Martin

William A Waters

Joseph P Lorenzo

Andrew Richard Davis

A vertical structure Schottky contact photodiode has a narrow bandgap InGaAs light absorbing layer cladded front and back with InAlAs current blocking layers having metal contacts formed thereon. As compared to single-side MSM photodiodes, with interdigitated electrodes lying in a single plane, response time is improved due to reduced spacing between the electrodes. Response time is also improved since capacitance is reduced due to inherently low doping levels in the semiconductor material. Laterally offset finger electrodes are made light reflective to increase the production of carriers in the InGaAs absorption layer.

Vertical structure schottky diode optical detector

An InP buffer layer is first formed upon an InP substrate; a thin layer of heavily doped InGaAs, a thick layer of light absorbing InGaAs, and a thin layer of InAlAs are thereafter sequentially grown upon the InP buffer layer. A light reflective Schottky barrier metallic layer is then applied to the InAlAs layer and the resulting device is inverted and affixed to a newly provided substrate, to thus shield and protect the sensitive Schottky contact. The InP substrate layers are thereafter removed and the now exposed thin, heavily doped InGaAs layer is coated with a transparent, electrically conductive layer of Indium-tin-oxide.

Transparent ohmic contacts for Schottky diode optical detectors on thin

A system for functionally testing opto-electronic devices, such as fiber-optic infrared receiver photodiodes, in the integral wafer or other optical port-exposed status. The testing arrangement uses a portable optical probe for communicating optical signals between the testing apparatus and the tested device in coincidence with electrical energization and functional operation of the electro-optical device by the test apparatus. The optical probe signals may be correlated in time relationship or other manner with the electrical signals applied-to the device-under-test. The invention provides simple conversion between a conventional electrical semiconductor device probe station and an electro-optical device probe station.

Infrared receiver wafer level probe testing

A photo FET device having a large area backside optical energy reception surface is disclosed. The photo FET device is fabricated in the source gate and drain upward configuration using a lattice determining surrogate substrate and a mesa-forming deep etch processing sequence and then inverted onto a new permanent substrate member and the surrogate substrate member removed in order to expose the active area backside optical energy reception surface. Fabrication of the device from two possible indium-inclusive semiconductor materials and a particular gate metal alloy is also disclosed.

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Nashua, NH, United States of America

Stephen M Spaziani