US 4,966,862 A · Method of production of light emitting diodes

Abstract

The invention is a method for preparing a plurality of light emitting diodes on a single substrate of a semiconductor material. The method is used for structures where the substrate includes an epitaxial layer of the same semiconductor material that in turn comprises layers of p-type and n-type material that define a p-n junction therebetween. The epitaxial layer and the substrate are etched in a predetermined pattern to define individual diode precursors, and deeply enough to form mesas in the epitaxial layer that delineate the p-n junctions in each diode precursor from one another. The substrate is then grooved from the side of the epitaxial layer and between the mesas to a predetermined depth to define side portions of diode precursors in the substrate while retaining enough of the substrate beneath the grooves to maintain its mechanical stability. Ohmic contacts are added to the epitaxial layer and to the substrate and a layer of insulating material is formed on the diode precursor. The insulating layer covers the portions of the epitaxial layer that are not covered by the ohmic contact, any portions of the one surface of the substrate adjacent the mesas, and the side portions of the substrate. As a result, the junction and the side portions of the substrate of each diode are insulated from electrical contact other than through the ohmic contacts. When the diodes are separated they can be conventionally mounted with the junction side down in a conductive epoxy without concern that the epoxy will short circuit the resulting diode.

Claims16

Dependent claims

A method for preparing a plurality of light emitting diodes on a single substrate of a semiconductor material having a p or n conductivity type, and in which the resulting diodes can be separated and mechanically fixed to transmit from their substrate side rather than the junction side using otherwise conventional mounting techniques, and wherein the substrate includes an epitaxial layer of the same semiconductor material on one surface thereof in which the epitaxial layer comprises a layer of p-type material and a layer of n-type material adjacent one another and that form a p-n junction therebetween, the method comprising;

etching the epitaxial layer and the substantially transparent substrate in a predetermined pattern to define individual diode precursors and wherein the etch is deep enough to form mesas in the epitaxial layer that delineate the p-n junctions in each diode precursor from one another;
grooving the substrate from the side of the epitaxial layer and between the mesas of the diode precursors to a predetermined depth into the substrate to define side portions of the device precursors in the substrate while retaining enough of the substrate beneath the grooves to maintain the mechanical stability of the substrate;
adding an ohmic contact to the epitaxial layer;
forming a layer of an insulating material that covers the portions of the epitaxial layer that are not covered by the ohmic contact and that covers any portions of the one surface of the substrate adjacent the mesas that are not covered by the epitaxial layer and that covers portions of the side portions of the substrate for insulating the one surface, the junction and the side portions of the substrate of each diode precursor from electrical contact other than through the ohmic contact;
and
adding an ohmic contact to the substrate.

3 more elements

A method for preparing a plurality of blue light emitting diodes on a single substrate, and in which the resulting diodes can be separated and mechanically fixed to transmit from their substrate side rather than the junction side using otherwise conventional mounting techniques, the method comprising:

forming an epitaxial layer of alpha silicon carbide on one surface of a substantially transparent silicon carbide substrate having a p or n type conductivity in which the epitaxial layer comprises a layer of p-type silicon carbide and a layer of n-type silicon carbide adjacent one another and that form a p-n junction therebetween;
etching the epitaxial layer and the substrate in a predetermined pattern to define individual diode precursors and wherein the etch is deep enough to form mesas in the epitaxial layer that delineate the p-n junctions in each diode precursor from one another;
grooving the substrate from the side of the epitaxial layer and between the mesas of the diode precursors to a predetermined depth into the substrate to define side portions of the device precursors in the substrate while retaining enough of the substrate beneath the grooves to maintain the mechanical stability of the substrate;
adding an ohmic contact to the epitaxial layer;
forming a layer of an insulating material that covers the portions of the epitaxial layer that are not covered by the ohmic contact and that covers any portions of the one surface of the substrate adjacent the mesas that are not covered by the epitaxial layer and that covers portions of the side portions of the substrate for insulating the one surface, the junction and the side portions of the substrate of each diode precursor from electrical contact other than through the ohmic contact;
and
adding an ohmic contact to the substrate.

4 more elements

Dependencies are inferred from the claim text.

Method of production of light emitting diodes

Life of this patent

Method of production of light emitting diodes

Life of this patent

Abstract

Claims16