Georgia Tech Research Corporation

Innovative Advanced Materials, Inc.

Other

William Alan Doolittle

Chloe A M Fabien

Joseph J Merola

Evan A Clinton

Brendan Patrick Gunning

Michael William Moseley

Ajeet Rohatgi

Gon Namkoong

Systems and methods for the rapid growth of Group III metal nitrides using plasma assisted molecular beam epitaxy. The disclosure includes higher pressure and flow rates of nitrogen in the plasma, and the application of mixtures of nitrogen and an inert gas. Growth rates exceeding 8 &#x3bc;m/hour can be achieved.

System and method for increasing group III-nitride semiconductor growth rate and reducing damaging ion flux

Systems and methods are disclosed for rapid growth of Group III metal nitrides using plasma assisted molecular beam epitaxy. The disclosure includes higher pressure and flow rates of nitrogen in the plasma, and the application of mixtures of nitrogen and an inert gas. Growth rates exceeding 8 &#x3bc;m/hour can be achieved.

System and method for increasing III-nitride semiconductor growth rate and reducing damaging ion flux

An effusion cell includes a crucible for containing material to be evaporated or sublimated, a delivery tube configured to deliver evaporated or sublimated material originating from the crucible into a chamber, a supply tube extending from the crucible, the supply tube located and configured to trap condensate originating from the evaporated or sublimated material and to deliver the condensate back to the crucible, and at least one heating element located and configured to heat material in the crucible so as to cause evaporation or sublimation of the material and flow of the evaporated or sublimated material through the delivery tube and out from the effusion cell. The effusion cell is configured such that the crucible can be filled with the material to be evaporated or sublimated without removing the effusion cell from the process vacuum chamber. Semiconductor substrate processing systems may include such effusion cells.

Effusion cells, deposition systems including effusion cells, and related methods

A physical vapor deposition system includes a deposition chamber; a wafer support structure disposed within the deposition chamber and configured to support at least one wafer thereon, and at least one effusion cell disposed at least partially outside the deposition chamber and coupled to a wall of the deposition chamber. The at least one effusion cell is configured to generate physical vapor by evaporation or sublimation of material within the at least one effusion cell, and to inject the physical vapor into the deposition chamber through an aperture in the wall of the deposition chamber. The at least one effusion cell is configured such that the at least one effusion cell can be filled with the material to be evaporated or sublimated without removing the at least one effusion cell from the deposition chamber and without interrupting a deposition process performed using the deposition system.

Deposition systems including effusion sources, and related methods

Systems and methods for MBE growing of group-III Nitride alloys, comprising establishing an average reaction temperature range from about 250 C to about 850 C; introducing a nitrogen flux at a nitrogen flow rate; introducing a first metal flux at a first metal flow rate; and periodically stopping and restarting the first metal flux according to a first flow duty cycle. According to another embodiment, the system comprises a nitrogen source that provides nitrogen at a nitrogen flow rate, and, a first metal source comprising a first metal effusion cell that provides a first metal at a first metal flow rate, and a first metal shutter that periodically opens and closes according to a first flow duty cycle to abate and recommence the flow of the first metal from the first metal source. Produced alloys include AlN, InN, GaN, InGaN, and AlInGaN.

Systems and methods for growing a non-phase separated group-III nitride semiconductor alloy

Methods for growing a non-phase separated group-III nitride semiconductor alloy

A light-emitting nitride/zinc oxide based compound semiconductor device of double heterostructure. The double-heterostructure includes a light-emitting layer formed of an AlInGaN; 0&#x2266;x&#x3c;1, 0&#x3c;y&#x2266;1, and x+y=0.1 to 1 compound semiconductor doped an impurity. Single or multi quantum well light-emitting active layers AlInGaN/GaN; 0&#x2266;x&#x3c;1, 0&#x3c;y&#x2266;1, and x+y=0.1 to 1 are positioned between p-type GaN and n-type ZnO substrates.

Nitride/zinc oxide based light-emitting diodes

Semiconductor devices formed by depositing III-nitride compounds on lithium niobate and/or lithium tantalate substrates are disclosed. Also disclosed, are semiconductor devices formed by depositing lithium niobate and/or lithium tantalate on III-Nitrides and Silicon Carbide substrates. The semiconductor devices provide good lattice matching characteristics between the substrate and the material that is deposited upon the substrate. The method of forming such semiconductor devices, which is also disclosed, enables fabrication of periodically-poled devices in a manner that is advantageous in comparison to existing technologies.

Semiconductor devices formed of III-nitride compounds, lithium-niobate-tantalate, and silicon carbide

A composite aircraft comprising an aerostat containing a lighter than air gas, and a rotor assembly mounted to and below the aerostat, via an axle. The aerostat provides buoyancy to lift the weight of the aircraft plus a significant portion of the payload connected to the aircraft. The rotor assembly statically connects to the aerostat in all aspects except rotationally about the axle, and provides the remaining lift and propulsion to the aircraft and payload. The rotor assembly includes a hub, a plurality of blades, a plurality of winglets, and engine-powered propellers that provide rotational thrust to the rotor assembly. The plurality of blades and winglets have adjustable angles of attack to generate lift and forward propulsion to the aircraft. The blades mount radially from the axle and horizontally from an outboard end of the hub. The winglets mount above and below each blade. The engine-powered propellers mount to the outboard end of the hub. A center mast passes through the poles of the aerostat, mounts the aerostat, and supports the blades through cables. A control cab connects below the rotor assembly and controls the operation of the components of the aircraft. A plurality of sling cables connect the blades to the payload. The aircraft can lift payloads weighing up to 1,000,000 pounds, while moving at slow to moderate forward speeds.

Rotor--aerostat composite aircraft

A computer-based deep level transient spectroscopy (DLTS) system (10) efficiently digitizes and analyzes capacitance and conductance transients acquired from a test material (13) by conventional DLTS methods as well as by several transient methods, including a covariance method of linear predictive modeling. A unique pseudo-logarithmic data storage scheme allows each transient to be tested at more than eleven different rates, permitting three to five decades of time constants .tau. to be observed during each thermal scan, thereby allowing high resolution of closely spaced defect energy levels. The system (10) comprises a sensor (12) for detecting capacitance and/or conductance transients, a digitizing mechanism (14) for digitizing the capacitance and/or conductance transients, preamplifiers (16a, 16b) for filtering, amplifying, and for forwarding the transients to the digitizing mechanism (14), a pulse generator (18) for supplying a filling pulse to the test material (13) in a cryostat (24), a trigger conditioner for coordinating the timing between the digitizing mechanism (14) and the pulse generator (18), and a temperature controller (26) for changing the temperature of the cryostat (24).

Growing community of inventors

Hampton, GA, United States of America

William Alan Doolittle