Browse Prior Art Database

Blue and Ultraviolet Electroluminescent Diode

IP.com Disclosure Number: IPCOM000082908D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Rutz, RF: AUTHOR

Abstract

Aluminum nitride is a wide bandgap semiconductor that heretofore has not been very conductive in single crystal form. Using a known close-spaced pyrolytic transfer method of growth similar to that shown in U. S. Patent 3,577,285, issued May 4, 1971, to R. Rutz, but modified by using a tungsten crucible and lid with carbon contamination being avoided, aluminum nitride has been grown that is conductive at room temperature and more conductive at temperatures of a few hundred degrees centigrade.

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Blue and Ultraviolet Electroluminescent Diode

Aluminum nitride is a wide bandgap semiconductor that heretofore has not been very conductive in single crystal form. Using a known close-spaced pyrolytic transfer method of growth similar to that shown in U. S. Patent 3,577,285, issued May 4, 1971, to R. Rutz, but modified by using a tungsten crucible and lid with carbon contamination being avoided, aluminum nitride has been grown that is conductive at room temperature and more conductive at temperatures of a few hundred degrees centigrade.

Using alloyed aluminum contacts made in an argon forming gas atmosphere, blue light emission is observed with the application of a DC voltage. Spectral measurements show this emission to be peaked at approximately 4600 angstroms with a short wavelength portion that extends into the ultraviolet region, as least as far as 2950 angstroms. Measurements on one diode indicated an electroluminescent peak at 4800 angstroms with a cathode luminescence peak at 3583 angstroms.

The most conductive diodes were grown in a tungsten crucible with only the sintered aluminum nitride source and the substrate present. The presence of carbon or excess aluminum tends to promote very high resistance o that very little current flows. Fig. 1 of the drawing shows the crucible on cross-section and Fig. 2 shows the construction of a diode. The tungsten substrate is etched off in hydrofluoric and nitric acid and the crystal is then alloyed to a new tungsten t...