Medical University of South Carolina

Nitek, Inc.

Vinod Adivarahan

Asif Khan

Qhalid Fareed

M Asif Khan

Grigory Simin

Naveen Tipirneni

Alexander Lunev

Bin Zhang

Naveen Tipimeni

Rubina Khan

Iftikhar Ahmad

An ultraviolet light emitting semiconductor chip, its use in a LED, and methods of its fabrication are disclosed. The semiconductor chip can include a buffer layer of AlGaN, where 0&#x3c;x&#x2264;1 having a thickness from about 10 &#x3bc;m to about 3 mm and defining apertures in the thickness of the buffer layer formed due to lateral overgrowth of the buffer layer over a grooved basal substrate. A n-junction LED layer overlying the buffer layer, a multiple quantum well LED layer overlying the n-junction LED layer, and a p-junction LED layer overlying the multiple quantum well LED layer are also included in the chip, where all of the LED layers comprise AlGaN, where 0&#x3c;x&#x2264;1.

Ultraviolet light emitting devices and methods of fabrication

Fabrication methods of a high frequency (sub-micron gate length) operation of AlInGaN/InGaN/GaN MOS-DHFET, and the HFET device resulting from the fabrication methods, are generally disclosed. The method of forming the HFET device generally includes a novel double-recess etching and a pulsed deposition of an ultra-thin, high-quality silicon dioxide layer as the active gate-insulator. The methods of the present invention can be utilized to form any suitable field effect transistor (FET), and are particular suited for forming high electron mobility transistors (HEMT).

Fabrication technique for high frequency, high power group III nitride electronic devices

A template for a semiconductor device is made by providing an AGN substrate, growing a first layer of Group III nitrides on the substrate, depositing a thin metal layer on the first layer, annealing the metal such as gold so that it agglomerates to form a pattern of islands on the first layer; transferring the pattern into the first layer by etching then removing excess metal; and then depositing a second Group III nitride layer on the first layer. The second layer, through lateral overgrowth, coalesces over the gaps in the island pattern leaving a smooth surface with low defect density. A Group III semiconductor device may then be grown on the template, which may then be removed. Chlorine gas may be used for etching the pattern in the first layer and the remaining gold removed with aqua regia.

Semiconductor and template for growing semiconductors

MOSHFET devices are provided, along with their methods of fabrication. The MOSHFET device can include a substrate; a multilayer stack on the substrate; a ultra-thin barrier layer on the multilayer stack, wherein the ultra-thin barrier layer has a thickness of about 0.5 nm to about 10 nm; a dielectric, discontinuous thin film layer on portions of the ultra-thin barrier layer, wherein the dielectric, discontinuous thin film layer comprises SiO; a plurality of source electrodes and drain electrodes formed directly on the ultra-thin barrier layer in an alternating pattern such that the dielectric, discontinuous thin film layer is positioned between adjacent source electrodes and drain electrodes; a plurality of gate electrodes on the dielectric, discontinuous thin film layer; and a gate interconnect electrically connecting the plurality of gate electrodes.

Multi-finger large periphery AlInN/AlN/GaN metal-oxide-semiconductor heterostructure field effect transistors on sapphire substrate

Methods for forming a HEMT device are provided. The method includes forming an ultra-thin barrier layer on the plurality of thin film layers. A dielectric thin film layer is formed over a portion of the ultra-thin barrier layer to leave exposed areas of the ultra-thin barrier layer. A SAG S-D thin film layer is formed over the exposed areas of the ultra-thin barrier layer while leaving the dielectric thin film layer exposed. The dielectric thin film layer is then removed to expose the underlying ultra-thin barrier layer. The underlying ultra-thin barrier layer is treating with fluorine to form a treated area. A source and drain is added on the SAG S-D thin film layer, and a dielectric coating is deposited over the ultra-thin barrier layer treated with fluorine such that the dielectric coating is positioned between the source and the drain.

Selectively area regrown III-nitride high electron mobility transistor

An ultraviolet light emitting semiconductor chip, its use in a LED, and methods of its fabrication are disclosed. The semiconductor chip can include a buffer layer of AlGaN, where 0&#x3c;x&#x2266;1 having a thickness from about 10 &#x3bc;m to about 3 mm and defining apertures in the thickness of the buffer layer formed due to lateral overgrowth of the buffer layer over a grooved basal substrate. A n-junction LED layer overlying the buffer layer, a multiple quantum well LED layer overlying the n-junction LED layer, and a p-junction LED layer overlying the multiple quantum well LED layer are also included in the chip, where all of the LED layers comprise AlGaN, where 0&#x3c;x&#x2266;1.

Utlraviolet light emitting devices and methods of fabrication

An improved process for forming a UV emitting diode is described. The process includes providing a substrate. A super-lattice is formed directly on the substrate at a temperature of at least 800 to no more than 1,300&#xb0; C. wherein the super-lattice comprises AlInGaN wherein 0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;1 and 0&#x3c;x+y&#x2266;1. A first conductive layer with a first type of conductivity is formed on the super-lattice wherein the first conductive layer comprises AlInGaN wherein 0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;1 and 0&#x3c;x+y&#x2266;1. A quantum well region is formed on the first conductive layer wherein the quantum well region comprises AlInGaN wherein 0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;1 and 0&#x3c;x+y&#x2266;1. A second conductive layer is formed on the quantum well with a second type of conductivity wherein the second conductive layer comprises AlInGaN wherein 0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;1 and 0&#x3c;x+y&#x2266;1. A first metal contact is formed in electrical contact with the first conductive layer and a second metal contact is formed in electrical contact with the second conductive layer.

High power ultraviolet light emitting diode with superlattice

The present invention is generally directed to methods of selectively doping a substrate and the resulting selectively doped substrates. The methods include doping an epilayer of a substrate with the selected doping material to adjust the conductivity of either the epilayers grown over a substrate or the substrate itself. The methods utilize lithography to control the location of the doped regions on the substrate. The process steps can be repeated to form a cyclic method of selectively doping different areas of the substrate with the same or different doping materials to further adjust the properties of the resulting substrate.

Selectively doped semi-conductors and methods of making the same

Ultraviolet light emitting illuminator, and method for fabricating same, comprises an array of ultraviolet light emitting diodes and a first and second terminal. When an alternating current is applied across the first and second terminals and thus to each of the diodes, the illuminator emits ultraviolet light at a frequency corresponding to that of the alternating current. The illuminator includes a template with ultraviolet light emitting quantum wells, a first buffer layer with a first type of conductivity and a second buffer layer with a second type of conductivity, all deposited preferably over strain-relieving layer. A first and second metal contact are applied to the semiconductor layers having the first and second type of conductivity, respectively, to complete the LED. The emission spectrum ranges from 190 nm to 369 nm. The illuminator may be configured in various materials, geometries, sizes and designs.

Ultraviolet light emitting diode with AC voltage operation

Methods of achieving high breakdown voltages in semiconductor devices by suppressing the surface flashover using high dielectric strength insulating encapsulation material are generally described. In one embodiment of the present invention, surface flashover in AlGaN/GaN heterostructure field-effect transistors (HFETs) is suppressed by using high dielectric strength insulating encapsulation material. Surface flashover in as-fabricated III-Nitride based HFETs limits the operating voltages at levels well below the breakdown voltages of GaN.

Method to increase breakdown voltage of semiconductor devices

A vertically conducting LED comprising, in a layered arrangement: a highly thermally conductive submount wherein the highly conductive submount has a thermal conductivity of at least 100 W/mK; a p-type layer comprising AlInGaN wherein 0&#x2266;x&#x2266;1 and 0&#x2266;y&#x2266;1; a quantum well layer comprising AlInGaN wherein 0&#x2266;x&#x2266;1 and 0&#x2266;y&#x2266;1; an n-type layer comprising AlInGaN wherein 0&#x2266;x&#x2266;1 and 0&#x2266;y&#x2266;1; and an n-type contact layer wherein the LED has a peak emission at 200-365 nm.

High power ultraviolet light sources and method of fabricating the same

An improved high breakdown voltage semiconductor device and method for manufacturing is provided. The device has a substrate and a AlGaN layer on the substrate wherein 0.1&#x2266;a&#x2266;1.00. A GaN layer is on the AlGaN layer. An InGaN/GaN channel layer is on the GaN layer wherein 0.1&#x2266;b&#x2266;1.00. A AlInGaN spacer layer is on the InGaN/GaN layer wherein 0.1&#x2266;c&#x2266;1.00 and 0.0&#x2266;d&#x2266;0.99. A AlInN nested superlattice barrier layer is on the AlInGaN spacer layer wherein 0.10&#x2266;e&#x2266;0.99. A AlInGaN leakage suppression layer is on the AlInN barrier layer wherein 0.1&#x2266;f&#x2266;0.99 and 0.1&#x2266;g&#x2266;0.99 wherein the leakage suppression layer decreases leakage current and increases breakdown voltage during high voltage operation. A superstructure, preferably with metallic electrodes, is on the AlInGaN leakage suppression layer.

Multilayer barrier III-nitride transistor for high voltage electronics

Ultraviolet light emitting illuminator, and method for fabricating same, comprises an array of ultraviolet light emitting diodes and a first and a second terminal. When an alternating current is applied across the first and second terminals and thus to each of the diodes, the illuminator emits ultraviolet light at a frequency corresponding to that of the alternating current. The illuminator includes a template with ultraviolet light emitting quantum wells, a first buffer layer with a first type of conductivity and a second buffer layer with a second type of conductivity, all deposited preferably over a strain-relieving layer. A first and second metal contact are applied to the semiconductor layers having the first and second type of conductivity, respectively, to complete the LED. The emission spectrum ranges from 190 nm to 369 nm. The illuminator may be configured in various materials, geometries, sizes and designs.

Growing community of inventors

Columbia, SC, United States of America

Vinod Adivarahan