US 5,604,135 A · Method of forming green light emitting diode in silicon carbide

Abstract

A light emitting diode is disclosed that emits in the green portion of the visible spectrum, along with a method of producing the diode. The light emitting diode comprises a 6H silicon carbide substrate having a planar surface inclined more than one degree off axis toward one of the <11 20> directions; an ohmic contact to the substrate; a first epitaxial layer of 6H silicon carbide on the inclined surface of the substrate and having a first conductivity type; a second epitaxial layer of 6H silicon carbide on the first layer and having the opposite conductivity type for forming a p-n junction between the first and second layers; and an ohmic contact to the second epitaxial layer. The diode produces a peak wavelength of between about 525 and 535 nanometers with a spectral half width of no more than about 90 nanometers.

Claims17

Dependent claims

A method of producing a true green light emitting diode in silicon carbide, the method comprising:

depositing a first epitaxial layer of 6H silicon carbide having a first conductivity type on a prepared planar surface of a 6H silicon carbide substrate in which the planar surface is inclined more than one degree off axis with respect to a basal plane thereof substantially towards one of the <11 20>
directions;
directing an ion implantation beam of dopant ions onto the first epitaxial layer while maintaining the layer at a temperature high enough to position dopant atoms at substitutional lattice sites in the epitaxial layer but less than the temperature at which excessive graphitization of the silicon carbide would occur to produce an implanted layer on said first epitaxial layer having the opposite conductivity type from said first layer, and to thereby produce a p-n junction between said first layer and said implanted layer;
and
removing graphite from the surface of the implanted layer without affecting the electronic characteristics of the implanted layer or the junction.

2 more elements

A method of producing a true green light emitting diode in silicon carbide, the method comprising:

depositing a first epitaxial layer of 6H silicon carbide on a prepared planar surface of a 6H silicon carbide substrate in which the planar surface is inclined more than one degree off axis with respect to a basal plane thereof substantially towards one of the <11 20>
directions;
directing an ion implantation beam of dopant ions onto the first epitaxial layer while maintaining the layer at a temperature high enough to position dopant atoms at substitutional lattice sites in the epitaxial layer but less than the temperature at which excessive graphitization of the silicon carbide would occur to produce an implanted layer on said first epitaxial layer having the opposite conductivity type from said first layer, and to thereby produce a p-n junction between said first layer and said implanted layer;
annealing the surface in the presence of a dopant that would produce a conductivity type the same as that of the dopant implanted;
and
depositing an additional epitaxial layer of 6H silicon carbide upon the implanted layer to encourage current spreading and the resulting light output of the diode.

3 more elements

Dependencies are inferred from the claim text.

Method of forming green light emitting diode in silicon carbide

Life of this patent

Method of forming green light emitting diode in silicon carbide

Life of this patent

Abstract

Claims17