Abstract: A white light emitting lamp is disclosed comprising a solid state ultra violet (UV) emitter that emits light in the UV wavelength spectrum. A conversion material is arranged to absorb at least some of the light emitting from the UV emitter and re-emit light at one or more different wavelengths of light. One or more complimentary solid state emitters are included that emit at different wavelengths of light than the UV emitter and the conversion material. The lamp emits a white light combination of light emitted from the complimentary emitters and from the conversion material, with the white light having high efficacy and good color rendering. Other embodiments of white light emitting lamp according to the present invention comprises a solid state laser instead of a UV emitter. A high flux white emitting lamp embodiment according to the invention comprises a large area light emitting diode (LED) that emits light at a first wavelength spectrum and includes a conversion material.

Abstract: The present invention discloses a susceptor mounting assembly for holding semiconductor wafers in an MOCVD reactor during growth of epitaxial layers on the wafers, that is particularly adapted for mounting a susceptor in an inverted type reactor chamber. It includes a tower having an upper and lower end with the upper end mounted to the top inside surface of the reactor chamber and a susceptor is arranged at the tower's lower end. Semiconductor wafers are held adjacent to the susceptor such that heat from the susceptor passes into wafers. A second embodiment of a susceptor mounting assembly according to the invention also comprises a tower having an upper and lower end. The tower's upper end is mounted to the top inside surface of the reactor chamber. A susceptor is housed within a cup and the cup is mounted to the tower's lower end.

Abstract: A flip-chip integrated circuit and method for fabricating the integrated circuit are disclosed. A method according to the invention comprises forming a plurality of active semiconductor devices on a wafer and separating the active semiconductor devices. Passive components and interconnections are formed on a surface of a circuit substrate and at least one conductive via is formed through the circuit substrate. At least one of the active semiconductor devices is flip-chip mounted on the circuit substrate with at least one of the bonding pads in electrical contact with one of the conductive vias. A flip-chip integrated circuit according to the present invention comprises a circuit substrate having passive components and interconnections on one surface and can have a conductive via through it. An active semiconductor device is flip-chip mounted on the circuit substrate, one of the at least one vias is in contact with one of the at least one the device's terminals.

Abstract: An LED with improved current spreading structures that provide enhanced current injection into the LED's active layer, improving its power and luminous flux. The current spreading structures can be used in LEDs larger than conventional LEDs while maintaining the enhanced current injection. The invention is particularly applicable to LEDs having insulating substrates but can also reduce the series resistance of LEDs having conductive substrates. The improved structures comprise conductive fingers that form cooperating conductive paths that ensure that current spreads from the p-type and n-type contacts into the fingers and uniformly spreads though the oppositely doped layers. The current then spreads to the active layer to uniformly inject electrons and holes throughout the active layer, which recombine to emit light.

Abstract: New Group III based diodes are disclosed having a low on state voltage (Vf) and structures to keep reverse current (Irev) relatively low. One embodiment of the invention is Schottky barrier diode made from the GaN material system in which the Fermi level (or surface potential) of is not pinned. The barrier potential at the metal-to-semiconductor junction varies depending on the type of metal used and using particular metals lowers the diode's Schottky barrier potential and results in a Vf in the range of 0.1-0.3V. In another embodiment a trench structure is formed on the Schottky diodes semiconductor material to reduce reverse leakage current. and comprises a number of parallel, equally spaced trenches with mesa regions between adjacent trenches. A third embodiment of the invention provides a GaN tunnel diode with a low Vf resulting from the tunneling of electrons through the barrier potential, instead of over it. This embodiment can also have a trench structure to reduce reverse leakage current.

Abstract: A semiconductor fabrication reactor according to the invention comprises a rotatable susceptor mounted to the top of a reactor chamber. One or more wafers are mounted to a surface of the susceptor and the rotation of the susceptor causes the wafers to rotate within the chamber. A heater heats the susceptor and a chamber gas inlet allows semiconductor growth gasses into the reactor chamber to deposit semiconductor material on said wafers. A chamber gas outlet is included to allow growth gasses to exit the chamber. In a preferred embodiment, the inlet is at or below the level of said wafers and the outlet is preferably at or above the level of the wafers. A semiconductor fabrication system according to the invention comprises a source of gasses for forming epitaxial layers on wafers and a source of gasses for dopants in said epitaxial layers.

Abstract: This invention describes new LEDs having light extraction structures on or within the LED to increase its efficiency. The new light extraction structures provide surfaces for reflecting, refracting or scattering light into directions that are more favorable for the light to escape into the package. The structures can be arrays of light extraction elements or disperser layers. The light extraction elements can have many different shapes and are placed in many locations to increase the efficiency of the LED over conventional LEDs. The disperser layers provide scattering centers for light and can be placed in many locations as well. The new LEDs with arrays of light extraction elements are fabricated with standard processing techniques making them highly manufacturable at costs similar to standard LEDs. The new LEDs with disperser layers are manufactured using new methods and are also highly manufacturable.

Abstract: A high efficiency, high yield solid state emitter package is disclosed exhibiting limited wavelength variations between batches and consistent wavelength and emission characteristics with operation. One embodiment of an emitter package according to the present invention comprises a semiconductor emitter and a conversion material. The conversion material is arranged to absorb substantially all of the light emitting from the semiconductor emitter and re-emit light at one or more different wavelength spectrums of light The conversion material is also arranged so that there is not an excess of conversion material to block the re-emitted light as it emits from the emitter package. The emitter package emitting light at one or more wavelength spectrums from the conversion material's re-emitted light.

Abstract: This invention describes new LEDs having light extraction structures on or within the LED to increase its efficiency. The new light extraction structures provide surfaces for reflecting, refracting or scattering light into directions that are more favorable for the light to escape into the package. The structures can be arrays of light extraction elements or disperser layers. The light extraction elements can have many different shapes and are placed in many locations to increase the efficiency of the LED over conventional LEDs. The disperser layers provide scattering centers for light and can be placed in many locations as well. The new LEDs with arrays of light extraction elements are fabricated with standard processing techniques making them highly manufacturable at costs similar to standard LEDs. The new LEDs with disperser layers are manufactured using new methods and are also highly manufacturable.

Abstract: A susceptor for holding semiconductor wafers in an MOCVD reactor during growth of epitaxial layers on the wafers is disclosed. The susceptor comprises a base structure made of a material having low thermal conductivity at high temperature, and has one or more plate holes to house heat transfer plugs. The plugs are made of a material with high thermal conductivity at high temperatures to transfer heat to the semiconductor wafers. A metalorganic organic chemical vapor deposition reactor is also disclosed utilizing a susceptor according to the present invention.

Abstract: An LED with improved current spreading structures that provide enhanced current injection into the LED's active layer, improving its power and luminous flux. The current spreading structures can be used in LEDs larger than conventional LEDs while maintaining the enhanced current injection. The invention is particularly applicable to LEDs having insulating substrates but can also reduce the series resistance of LEDs having conductive substrates. The improved structures comprise conductive fingers that form cooperating conductive paths that ensure that current spreads from the p-type and n-type contacts into the fingers and uniformly spreads though the oppositely doped layers. The current then spreads to the active layer to uniformly inject electrons and holes throughout the active layer, which recombine to emit light.

Abstract: New Group III nitride based field effect transistors and high electron mobility transistors are disclosed that provide enhanced high frequency response characteristics. The preferred transistors are made from GaN/AlGaN and have a dielectric layer on the surface of their conductive channels. The dielectric layer has a high percentage of donor electrons that neutralize traps in the conductive channel such that the traps cannot slow the high frequency response of the transistors. A new method of manufacturing the transistors is also disclosed, with the new method using sputtering to deposit the dielectric layer.

Abstract: New Group III based diodes are disclosed having a low on state voltage (Vf, and structures to keep reverse current (Irev) relatively low. One embodiment of the invention is Schottky barrier diode made from the GaN material system in which the Fermi level (or surface potential) of is not pinned. The barrier potential at the metal-to-semiconductor junction varies depending on the type of metal used and using particular metals lowers the diode's Schottky barrier potential and results in a Vf in the range of 0.1-0.3V. In another embodiment a trench structure is formed on the Schottky diodes semiconductor material to reduce reverse leakage current. and comprises a number of parallel, equally spaced trenches with mesa regions between adjacent trenches. A third embodiment of the invention provides a GaN tunnel diode with a low Vf resulting from the tunneling of electrons through the barrier potential, instead of over it. This embodiment can also have a trench structure to reduce reverse leakage current.

Abstract: Naturally occurring polarization-induced electric fields in a semiconductor light emitter with crystal layers grown along a polar direction are reduced, canceled or reversed to improve the emitter's operating efficiency and carrier confinement. This is accomplished by reducing differences in the material compositions of adjacent crystal layers, grading one or more layers to generate space charges and quasi-fields that oppose polarization-induced charges, incorporating various impurities into the semiconductor that ionize into a charge state opposite to the polarization induced charges, inverting the sequence of charged atomic layers, inverting the growth sequence of n- and p-type layers in the device, employing a multilayer emission system instead of a uniform active region and/or changing the in-plane lattice constant of the material.

Abstract: A method for protecting the surface of a semiconductor material from damage and dopant passivation is described. A barrier layer of dense or reactive material is deposited on the semiconductor material shortly after growth in a growth reactor such as a MOCVD reactor, using the MOCVD source gasses. The barrier layer blocks the diffusion of hydrogen into the material. The reactor can then be cooled in a reactive or non-reactive gas ambience. The semiconductor material can then be removed from the reactor with little or no passivation of the dopant species. The barrier layer can be removed using a variety of etching processes, including wet chemical etching or can be left at the semiconductor material for surface protection. The barrier layer can also be a gettering layer that chemically binds hydrogen trapped in the semiconductor material and/or blocks hydrogen diffusion into the material.

Abstract: A method for protecting the surface of a semiconductor material from damage and dopant passivation is described. A barrier layer of dense or reactive material is deposited on the semiconductor material shortly after growth in a growth reactor such as a MOCVD reactor, using the MOCVD source gasses. The barrier layer blocks the diffusion of hydrogen into the material. The reactor can then be cooled in a reactive or non-reactive gas ambience. The semiconductor material can then be removed from the reactor with little or no passivation of the dopant species. The barrier layer can be removed using a variety of etching processes, including wet chemical etching or can be left at the semiconductor material for surface protection. The barrier layer can also be a gettering layer that chemically binds hydrogen trapped in the semiconductor material and/or blocks hydrogen diffusion into the material.

Abstract: A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an AlyGa1−yN (y=1 or y 1) layer on the GaN buffer layer. An AlxGa1−xN (0≦x≦0.5) barrier layer on to the AlyGa1−yN layer, opposite the GaN buffer layer, AlyGa1−yN layer having a higher Al concentration than that of the AlxGa1−xN barrier layer. A preferred AlyGa1−yN layer has y=1 or y≃1 and a preferred AlxGa1−xN barrier layer has 0≦x≦0.5. A 2DEG forms at the interface between the GaN buffer layer and the AlyGa1−yN layer. Respective source, drain and gate contacts are formed on the AlxGa1−xN barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the AlyGa1−yN layer and a nucleation layer between the AlxGa1−xN buffer layer and the substrate.

Abstract: This invention describes new LED structures that provide increased light extraction efficiency. The new LED structures include arrays of electrically interconnected micro-LEDs that have and active layer sandwiched between two oppositely doped layer. The micro-LEDs are formed on a first spreader layer with the bottom layer of the micro-LEDs in contact with the first spreader. A second spreader layer is formed over the micro-LEDs and in contact with their top layer. The first spreader layer is electrically isolated from the second spreader layer. Each of the spreader layers has a contact and when a bias is applied across the contacts, current spreads to the micro-LEDs and they emit light. The efficiency of the new LED is increased by the increased emission surface of the micro-LEDs. Light from each of the micro-LEDs active layer will reach a surface after travelling only a short distance, reducing total internal reflection of the light.

Abstract: The invention provides a new solid state lamp emitting a light useful for room illumination and other applications. It comprises a solid state Light Source which transmits light through a Separator to a Disperser that disperses the light in a desired pattern and/or changes its color. In one embodiment, the Light Source is a blue emitting LED operating with current high enough for room illumination, the Separator is a light pipe or fiber optic device, and the Disperser disperses the light radially and converts some of the blue light to yellow to produce a white light mixture. The Separator spaces the Light Source a sufficient distance from the Disperser such that heat from the Light Source will not transfer to the Disperser when the Light Source is carrying elevated currents necessary for room illumination.

Abstract: A solar blind p-i-n photodiode where the active i-region has a bandgap larger than the bandgap of one or both of the n-type and p-type regions. The preferred embodiment photodiode is GaN based and Al is added to the regions to obtain the desired bandgap profiles. Al is added to the i-region to obtain a bandgap large enough to be responsive to light in the solar blind spectrum. By having a smaller bandgap p-type and n-type region, the problems associated with growing highly doped AlGaN are avoided. In most embodiments the light incident on the photodiode illuminates the p-type region first. The p-type region is grown thin compared to conventional photodiodes which allows the majority of light incident to pass through the p-type region to the i-region. Light with sufficient energy will be detected in the i-region. The inventive photodiode can also be used in the fabrication of backside illuminated solar blind photodiodes that are useful for photodiode arrays.